diff --git a/go.mod b/go.mod
index 2d8f751..ab16313 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.12
 
 require (
 	github.com/go-test/deep v1.0.4
+	github.com/google/go-cmp v0.5.6
 	github.com/mailru/easyjson v0.7.7
 	golang.org/x/lint v0.0.0-20201208152925-83fdc39ff7b5 // indirect
 )
diff --git a/go.sum b/go.sum
index 5935c4c..f40338a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,11 @@
 github.com/go-test/deep v1.0.4 h1:u2CU3YKy9I2pmu9pX0eq50wCgjfGIt539SqR7FbHiho=
 github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
+github.com/mailru/easyjson v0.7.1 h1:mdxE1MF9o53iCb2Ghj1VfWvh7ZOwHpnVG/xwXrV90U8=
+github.com/mailru/easyjson v0.7.1/go.mod h1:KAzv3t3aY1NaHWoQz1+4F1ccyAH66Jk7yos7ldAVICs=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
@@ -18,3 +24,4 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7 h1:EBZoQjiKKPaLbPrbpssUfuHtwM6KV/vb4U85g/cigFY=
 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/openrtb/application.go b/openrtb/application.go
index d156a64..9bf7739 100644
--- a/openrtb/application.go
+++ b/openrtb/application.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Application object should be included if the ad supported content is a
 // non-browser application (typically in mobile) as opposed to a website.
@@ -134,7 +138,7 @@ type Application struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Application object contains required and well-formatted data
@@ -171,7 +175,7 @@ func (a *Application) Copy() *Application {
 	appCopy.Publisher = a.Publisher.Copy()
 	appCopy.Content = a.Content.Copy()
 
-	appCopy.Extension = util.DeepCopyCopiable(a.Extension)
+	appCopy.Extension = util.DeepCopyJSONRawMsg(a.Extension)
 
 	return &appCopy
 }
diff --git a/openrtb/application_easyjson.go b/openrtb/application_easyjson.go
index adf7dcf..8a5cd6b 100644
--- a/openrtb/application_easyjson.go
+++ b/openrtb/application_easyjson.go
@@ -148,12 +148,8 @@ func easyjsonB2e97d60DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Ap
 		case "keywords":
 			out.Keywords = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -332,7 +328,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in A
 		}
 		out.String(string(in.Keywords))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -340,13 +336,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in A
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -548,12 +538,8 @@ func easyjsonB2e97d60DecodeGithubComVungleVungoOpenrtb2(in *jlexer.Lexer, out *C
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -837,7 +823,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -845,13 +831,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -910,12 +890,8 @@ func easyjsonB2e97d60DecodeGithubComVungleVungoOpenrtb4(in *jlexer.Lexer, out *D
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -970,7 +946,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb4(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -978,13 +954,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb4(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1014,12 +984,8 @@ func easyjsonB2e97d60DecodeGithubComVungleVungoOpenrtb5(in *jlexer.Lexer, out *S
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1061,7 +1027,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb5(out *jwriter.Writer, in
 		}
 		out.String(string(in.Value))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1069,13 +1035,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb5(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1128,12 +1088,8 @@ func easyjsonB2e97d60DecodeGithubComVungleVungoOpenrtb3(in *jlexer.Lexer, out *P
 		case "domain":
 			out.Domain = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1194,7 +1150,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		}
 		out.String(string(in.Domain))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1202,13 +1158,7 @@ func easyjsonB2e97d60EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/audio.go b/openrtb/audio.go
index cc39a5e..14a88d8 100644
--- a/openrtb/audio.go
+++ b/openrtb/audio.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -185,7 +186,7 @@ type Audio struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -249,7 +250,7 @@ func (a *Audio) Copy() *Audio {
 		copy(vCopy.CompanionTypes, a.CompanionTypes)
 	}
 
-	vCopy.Extension = util.DeepCopyCopiable(a.Extension)
+	vCopy.Extension = util.DeepCopyJSONRawMsg(a.Extension)
 
 	return &vCopy
 }
diff --git a/openrtb/audio_easyjson.go b/openrtb/audio_easyjson.go
index bfbe854..b2b7b1c 100644
--- a/openrtb/audio_easyjson.go
+++ b/openrtb/audio_easyjson.go
@@ -246,12 +246,8 @@ func easyjson48f1e884DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Au
 		case "nvol":
 			out.NormalizedVolume = VolumeNormalizationMode(in.Int())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -422,16 +418,10 @@ func easyjson48f1e884EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in A
 		out.RawString(prefix)
 		out.Int(int(in.NormalizedVolume))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -685,12 +675,8 @@ func easyjson48f1e884DecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *B
 		case "vcm":
 			out.VCM = CompanionRenderingMode(in.Int())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -916,7 +902,7 @@ func easyjson48f1e884EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		}
 		out.Int(int(in.VCM))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -924,13 +910,7 @@ func easyjson48f1e884EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -964,12 +944,8 @@ func easyjson48f1e884DecodeGithubComVungleVungoOpenrtb2(in *jlexer.Lexer, out *F
 		case "wmin":
 			out.WMin = uint64(in.Uint64())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1031,7 +1007,7 @@ func easyjson48f1e884EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		}
 		out.Uint64(uint64(in.WMin))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1039,13 +1015,7 @@ func easyjson48f1e884EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/banner.go b/openrtb/banner.go
index aeacca2..c62ebd1 100644
--- a/openrtb/banner.go
+++ b/openrtb/banner.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -179,7 +180,7 @@ type Banner struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -213,10 +214,12 @@ func (v *Banner) Copy() *Banner {
 
 	if v.Format != nil {
 		vCopy.Format = make([]Format, len(v.Format))
-		copy(vCopy.Format, v.Format)
+		for i, format := range v.Format {
+			vCopy.Format[i] = *format.Copy()
+		}
 	}
 
-	vCopy.Extension = util.DeepCopyCopiable(v.Extension)
+	vCopy.Extension = util.DeepCopyJSONRawMsg(v.Extension)
 
 	return &vCopy
 }
diff --git a/openrtb/banner_easyjson.go b/openrtb/banner_easyjson.go
index e474fa1..31489ce 100644
--- a/openrtb/banner_easyjson.go
+++ b/openrtb/banner_easyjson.go
@@ -243,12 +243,8 @@ func easyjsonC16456caDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Ba
 		case "vcm":
 			out.VCM = CompanionRenderingMode(in.Int())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -474,7 +470,7 @@ func easyjsonC16456caEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in B
 		}
 		out.Int(int(in.VCM))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -482,13 +478,7 @@ func easyjsonC16456caEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in B
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -546,12 +536,8 @@ func easyjsonC16456caDecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *F
 		case "wmin":
 			out.WMin = uint64(in.Uint64())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -613,7 +599,7 @@ func easyjsonC16456caEncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		}
 		out.Uint64(uint64(in.WMin))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -621,13 +607,7 @@ func easyjsonC16456caEncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/bidrequest.go b/openrtb/bidrequest.go
index 089a782..275df28 100644
--- a/openrtb/bidrequest.go
+++ b/openrtb/bidrequest.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"fmt"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -218,7 +219,7 @@ type BidRequest struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the BidRequest object contains required and well-formatted data
@@ -285,6 +286,6 @@ func (r *BidRequest) Copy() *BidRequest {
 	brCopy.BlockedAdvertisersByMarketID = util.DeepCopyStrSlice(r.BlockedAdvertisersByMarketID)
 	brCopy.Regulation = r.Regulation.Copy()
 	brCopy.Source = r.Source.Copy()
-	brCopy.Extension = util.DeepCopyCopiable(r.Extension)
+	brCopy.Extension = util.DeepCopyJSONRawMsg(r.Extension)
 	return &brCopy
 }
diff --git a/openrtb/bidrequest_easyjson.go b/openrtb/bidrequest_easyjson.go
index 92d4c22..3ad1002 100644
--- a/openrtb/bidrequest_easyjson.go
+++ b/openrtb/bidrequest_easyjson.go
@@ -303,12 +303,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Bi
 				easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb6(in, out.Regulation)
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -497,16 +493,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in B
 		out.RawString(prefix)
 		easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb6(out, *in.Regulation)
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -566,12 +556,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb6(in *jlexer.Lexer, out *R
 				}
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -593,7 +579,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb6(out *jwriter.Writer, in
 		out.RawString(prefix[1:])
 		out.Raw((*in.IsCoppaCompliant).MarshalJSON())
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -601,13 +587,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb6(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -637,12 +617,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb5(in *jlexer.Lexer, out *S
 		case "pchain":
 			out.PChain = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -684,7 +660,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb5(out *jwriter.Writer, in
 		}
 		out.String(string(in.PChain))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -692,13 +668,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb5(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -767,12 +737,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb4(in *jlexer.Lexer, out *U
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -873,7 +839,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb4(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -881,13 +847,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb4(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -946,12 +906,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb8(in *jlexer.Lexer, out *D
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1006,7 +962,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb8(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1014,13 +970,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb8(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1050,12 +1000,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb9(in *jlexer.Lexer, out *S
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1097,7 +1043,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb9(out *jwriter.Writer, in
 		}
 		out.String(string(in.Value))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1105,13 +1051,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb9(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1161,12 +1101,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb7(in *jlexer.Lexer, out *G
 		case "utcoffset":
 			out.UTCOffset = int(in.Int())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1308,7 +1244,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb7(out *jwriter.Writer, in
 		}
 		out.Int(int(in.UTCOffset))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1316,13 +1252,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb7(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1456,12 +1386,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb3(in *jlexer.Lexer, out *D
 		case "macmd5":
 			out.MACMD5 = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1773,7 +1699,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		}
 		out.String(string(in.MACMD5))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -1781,13 +1707,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1938,12 +1858,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb2(in *jlexer.Lexer, out *S
 		case "keywords":
 			out.Keywords = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -2122,7 +2038,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		}
 		out.String(string(in.Keywords))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -2130,13 +2046,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -2314,12 +2224,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb11(in *jlexer.Lexer, out *
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -2603,7 +2509,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb11(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -2611,13 +2517,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb11(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -2670,12 +2570,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb12(in *jlexer.Lexer, out *
 		case "domain":
 			out.Domain = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -2736,7 +2632,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb12(out *jwriter.Writer, in
 		}
 		out.String(string(in.Domain))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -2744,13 +2640,7 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb12(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -3022,12 +2912,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *I
 		case "exp":
 			out.Exp = int(in.Int())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -3150,16 +3036,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		out.RawString(prefix)
 		out.Int(int(in.Exp))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -3218,12 +3098,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb16(in *jlexer.Lexer, out *
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -3264,16 +3140,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb16(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -3351,12 +3221,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb17(in *jlexer.Lexer, out *
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -3420,16 +3286,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb17(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -3503,12 +3363,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb15(in *jlexer.Lexer, out *
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -3562,16 +3418,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb15(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -3841,12 +3691,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb14(in *jlexer.Lexer, out *
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -4066,16 +3912,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb14(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -4105,12 +3945,8 @@ func easyjson89fe9b30DecodeGithubComVungleVungoOpenrtb13(in *jlexer.Lexer, out *
 		case "vendor":
 			out.Vendor = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -4141,16 +3977,10 @@ func easyjson89fe9b30EncodeGithubComVungleVungoOpenrtb13(out *jwriter.Writer, in
 		out.RawString(prefix)
 		out.String(string(in.Vendor))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/bidresponse.go b/openrtb/bidresponse.go
index b4f59d8..7018d1b 100644
--- a/openrtb/bidresponse.go
+++ b/openrtb/bidresponse.go
@@ -16,15 +16,13 @@ var emptyBid BidResponse
 //go:generate easyjson $GOFILE
 //easyjson:json
 type BidResponse struct {
-	ID          string       `json:"id"`
-	SeatBids    []*SeatBid   `json:"seatbid,omitempty"`
-	BidID       string       `json:"bidid,omitempty"`
-	Currency    Currency     `json:"cur,omitempty"`
-	CustomData  string       `json:"customdata,omitempty"`
-	NoBidReason *NoBidReason `json:"nbr,omitempty"`
-
-	RawExtension json.RawMessage `json:"ext,omitempty"`
-	Extension    interface{}     `json:"-"` // Opaque value that can be used to store unmarshaled value in ext field.
+	ID          string          `json:"id"`
+	SeatBids    []*SeatBid      `json:"seatbid,omitempty"`
+	BidID       string          `json:"bidid,omitempty"`
+	Currency    Currency        `json:"cur,omitempty"`
+	CustomData  string          `json:"customdata,omitempty"`
+	NoBidReason *NoBidReason    `json:"nbr,omitempty"`
+	Extension   json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method validates whether the BidResponse object contains valid data, or returns an
@@ -86,7 +84,7 @@ func (r *BidResponse) Copy() *BidResponse {
 	}
 
 	if r.Extension != nil {
-		brCopy.RawExtension = util.DeepCopyJSONRawMsg(r.RawExtension)
+		brCopy.Extension = util.DeepCopyJSONRawMsg(r.Extension)
 	}
 
 	return &brCopy
diff --git a/openrtb/bidresponse_easyjson.go b/openrtb/bidresponse_easyjson.go
index ac37151..d54c457 100644
--- a/openrtb/bidresponse_easyjson.go
+++ b/openrtb/bidresponse_easyjson.go
@@ -87,7 +87,7 @@ func easyjson10eb023eDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Bi
 			}
 		case "ext":
 			if data := in.Raw(); in.Ok() {
-				in.AddError((out.RawExtension).UnmarshalJSON(data))
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -146,10 +146,10 @@ func easyjson10eb023eEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in B
 		out.RawString(prefix)
 		out.Int(int(*in.NoBidReason))
 	}
-	if len(in.RawExtension) != 0 {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		out.Raw((in.RawExtension).MarshalJSON())
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/bidresponse_test.go b/openrtb/bidresponse_test.go
index 3143e3b..886debc 100644
--- a/openrtb/bidresponse_test.go
+++ b/openrtb/bidresponse_test.go
@@ -111,9 +111,7 @@ func TestBidResponse_Copy(t *testing.T) {
 	}
 
 	openrtbtest.FillWithNonNilValue(&bidResponse)
-	bidResponse.Extension = true // hack to workaround BidResponse specific Copy implementation about RawExtension
 	respCopy := bidResponse.Copy()
-	respCopy.Extension = true
 	if err := openrtbtest.VerifyDeepCopy(
 		&bidResponse, respCopy); err != nil {
 		t.Errorf("Copy() should be deep copy\n%v\n", err)
diff --git a/openrtb/content.go b/openrtb/content.go
index e0ba44a..4c0fc08 100644
--- a/openrtb/content.go
+++ b/openrtb/content.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Content object describes the content in which the impression will appear,
 // which may be syndicated or nonsyndicated content.
@@ -237,7 +241,7 @@ type Content struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Site object contains required and
@@ -267,6 +271,6 @@ func (c *Content) Copy() *Content {
 			cCopy.Data[i] = c.Data[i].Copy()
 		}
 	}
-	cCopy.Ext = util.DeepCopyCopiable(c.Ext)
+	cCopy.Ext = util.DeepCopyJSONRawMsg(c.Ext)
 	return &cCopy
 }
diff --git a/openrtb/content_easyjson.go b/openrtb/content_easyjson.go
index dfa591d..50af3a3 100644
--- a/openrtb/content_easyjson.go
+++ b/openrtb/content_easyjson.go
@@ -191,12 +191,8 @@ func easyjson344736e9DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Co
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -480,7 +476,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in C
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -488,13 +484,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in C
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -577,12 +567,8 @@ func easyjson344736e9DecodeGithubComVungleVungoOpenrtb2(in *jlexer.Lexer, out *D
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -637,7 +623,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -645,13 +631,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -681,12 +661,8 @@ func easyjson344736e9DecodeGithubComVungleVungoOpenrtb3(in *jlexer.Lexer, out *S
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -728,7 +704,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		}
 		out.String(string(in.Value))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -736,13 +712,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -795,12 +765,8 @@ func easyjson344736e9DecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *P
 		case "domain":
 			out.Domain = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -861,7 +827,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		}
 		out.String(string(in.Domain))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -869,13 +835,7 @@ func easyjson344736e9EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/data.go b/openrtb/data.go
index 3f7b27b..1f504c3 100644
--- a/openrtb/data.go
+++ b/openrtb/data.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Data object
 // The data and segment objects together allow additional data about the related
@@ -46,7 +50,7 @@ type Data struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Site object contains required and
@@ -69,6 +73,6 @@ func (d *Data) Copy() *Data {
 			dCopy.Segment[i] = d.Segment[i].Copy()
 		}
 	}
-	dCopy.Ext = util.DeepCopyCopiable(d.Ext)
+	dCopy.Ext = util.DeepCopyJSONRawMsg(d.Ext)
 	return &dCopy
 }
diff --git a/openrtb/data_easyjson.go b/openrtb/data_easyjson.go
index c793b49..9789e8a 100644
--- a/openrtb/data_easyjson.go
+++ b/openrtb/data_easyjson.go
@@ -72,12 +72,8 @@ func easyjson794297d0DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Da
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -132,7 +128,7 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in D
 			out.RawByte(']')
 		}
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -140,13 +136,7 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in D
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -200,12 +190,8 @@ func easyjson794297d0DecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *S
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -247,7 +233,7 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		}
 		out.String(string(in.Value))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -255,13 +241,7 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/deal.go b/openrtb/deal.go
index 9c53356..aa9be5a 100644
--- a/openrtb/deal.go
+++ b/openrtb/deal.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -75,7 +76,7 @@ type Deal struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -97,7 +98,7 @@ func (d *Deal) Copy() *Deal {
 	dealCopy := *d
 	dealCopy.WhitelistedSeats = util.DeepCopyStrSlice(d.WhitelistedSeats)
 	dealCopy.AdvertiserDomains = util.DeepCopyStrSlice(d.AdvertiserDomains)
-	dealCopy.Extension = util.DeepCopyCopiable(d.Extension)
+	dealCopy.Extension = util.DeepCopyJSONRawMsg(d.Extension)
 
 	return &dealCopy
 }
diff --git a/openrtb/deal_easyjson.go b/openrtb/deal_easyjson.go
index 8e46a2f..0ffecc2 100644
--- a/openrtb/deal_easyjson.go
+++ b/openrtb/deal_easyjson.go
@@ -91,12 +91,8 @@ func easyjson8a221a72DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *De
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -160,16 +156,10 @@ func easyjson8a221a72EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in D
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/device.go b/openrtb/device.go
index 5b8e042..9d396ac 100644
--- a/openrtb/device.go
+++ b/openrtb/device.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Device object provides information pertaining to the device through which the
 // user is interacting.
@@ -267,7 +271,7 @@ type Device struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy do deep copy of Device.
@@ -280,7 +284,7 @@ func (d *Device) Copy() *Device {
 	deviceCopy := *d
 
 	if d.Geo != nil {
-		geoCopy := *d.Geo
+		geoCopy := *d.Geo.Copy()
 		deviceCopy.Geo = &geoCopy
 	}
 
@@ -299,7 +303,7 @@ func (d *Device) Copy() *Device {
 		deviceCopy.SupportsJavaScript = &SupportsJavaScriptCopy
 	}
 	deviceCopy.GeoFetch = d.GeoFetch.Copy()
-	deviceCopy.Extension = util.DeepCopyCopiable(d.Extension)
+	deviceCopy.Extension = util.DeepCopyJSONRawMsg(d.Extension)
 
 	return &deviceCopy
 }
diff --git a/openrtb/device_easyjson.go b/openrtb/device_easyjson.go
index 5890a2e..9010484 100644
--- a/openrtb/device_easyjson.go
+++ b/openrtb/device_easyjson.go
@@ -147,12 +147,8 @@ func easyjson3073ac56DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *De
 		case "macmd5":
 			out.MACMD5 = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -464,7 +460,7 @@ func easyjson3073ac56EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in D
 		}
 		out.String(string(in.MACMD5))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -472,13 +468,7 @@ func easyjson3073ac56EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in D
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -552,12 +542,8 @@ func easyjson3073ac56DecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *G
 		case "utcoffset":
 			out.UTCOffset = int(in.Int())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -699,7 +685,7 @@ func easyjson3073ac56EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		}
 		out.Int(int(in.UTCOffset))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -707,13 +693,7 @@ func easyjson3073ac56EncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/format.go b/openrtb/format.go
index c96206d..71aa62f 100644
--- a/openrtb/format.go
+++ b/openrtb/format.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Format object represents an allowed size (i.e., height and width combination) or Flex Ad parameters for a banner impression.
 // These are typically used in an array where multiple sizes are permitted.
@@ -56,7 +60,7 @@ type Format struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy do deep copy of Format.
@@ -67,6 +71,6 @@ func (f *Format) Copy() *Format {
 		return nil
 	}
 	fCopy := *f
-	fCopy.Ext = util.DeepCopyCopiable(f.Ext)
+	fCopy.Ext = util.DeepCopyJSONRawMsg(f.Ext)
 	return &fCopy
 }
diff --git a/openrtb/format_easyjson.go b/openrtb/format_easyjson.go
index dee5a47..b57c766 100644
--- a/openrtb/format_easyjson.go
+++ b/openrtb/format_easyjson.go
@@ -47,12 +47,8 @@ func easyjson72863a49DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Fo
 		case "wmin":
 			out.WMin = uint64(in.Uint64())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -114,7 +110,7 @@ func easyjson72863a49EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in F
 		}
 		out.Uint64(uint64(in.WMin))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -122,13 +118,7 @@ func easyjson72863a49EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in F
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/geo.go b/openrtb/geo.go
index 27dcd10..520833a 100644
--- a/openrtb/geo.go
+++ b/openrtb/geo.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Geo object encapsulates various methods for specifying a geographic location.
 // When subordinate to a Device object, it indicates the location of the device
@@ -138,7 +142,7 @@ type Geo struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy do deep copy of Geo.
@@ -149,6 +153,6 @@ func (g *Geo) Copy() *Geo {
 		return nil
 	}
 	gCopy := *g
-	gCopy.Ext = util.DeepCopyCopiable(g.Ext)
+	gCopy.Ext = util.DeepCopyJSONRawMsg(g.Ext)
 	return &gCopy
 }
diff --git a/openrtb/geo_easyjson.go b/openrtb/geo_easyjson.go
index 076a32e..43a035c 100644
--- a/openrtb/geo_easyjson.go
+++ b/openrtb/geo_easyjson.go
@@ -63,12 +63,8 @@ func easyjsonA0535929DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Ge
 		case "utcoffset":
 			out.UTCOffset = int(in.Int())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -210,7 +206,7 @@ func easyjsonA0535929EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in G
 		}
 		out.Int(int(in.UTCOffset))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -218,13 +214,7 @@ func easyjsonA0535929EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in G
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/impression.go b/openrtb/impression.go
index 092bdc7..fa6b4ab 100644
--- a/openrtb/impression.go
+++ b/openrtb/impression.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Impression object describes an ad placement or impression being auctioned.
 // A single bid request can include multiple Imp objects, a use case for which
@@ -184,7 +188,7 @@ type Impression struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy returns a pointer to a copy of the Impression object.
@@ -210,7 +214,7 @@ func (imp *Impression) Copy() *Impression {
 	}
 	impressionCopy.IframeBuster = util.DeepCopyStrSlice(imp.IframeBuster)
 
-	impressionCopy.Extension = util.DeepCopyCopiable(imp.Extension)
+	impressionCopy.Extension = util.DeepCopyJSONRawMsg(imp.Extension)
 
 	return &impressionCopy
 }
diff --git a/openrtb/impression_easyjson.go b/openrtb/impression_easyjson.go
index 1439d04..482d2fb 100644
--- a/openrtb/impression_easyjson.go
+++ b/openrtb/impression_easyjson.go
@@ -173,12 +173,8 @@ func easyjson7ebaa60bDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Im
 		case "exp":
 			out.Exp = int(in.Int())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -301,16 +297,10 @@ func easyjson7ebaa60bEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in I
 		out.RawString(prefix)
 		out.Int(int(in.Exp))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -393,12 +383,8 @@ func easyjson7ebaa60bDecodeGithubComVungleVungoOpenrtb4(in *jlexer.Lexer, out *P
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -439,16 +425,10 @@ func easyjson7ebaa60bEncodeGithubComVungleVungoOpenrtb4(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -522,12 +502,8 @@ func easyjson7ebaa60bDecodeGithubComVungleVungoOpenrtb3(in *jlexer.Lexer, out *N
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -581,16 +557,10 @@ func easyjson7ebaa60bEncodeGithubComVungleVungoOpenrtb3(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -860,12 +830,8 @@ func easyjson7ebaa60bDecodeGithubComVungleVungoOpenrtb2(in *jlexer.Lexer, out *V
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1085,16 +1051,10 @@ func easyjson7ebaa60bEncodeGithubComVungleVungoOpenrtb2(out *jwriter.Writer, in
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -1124,12 +1084,8 @@ func easyjson7ebaa60bDecodeGithubComVungleVungoOpenrtb1(in *jlexer.Lexer, out *M
 		case "vendor":
 			out.Vendor = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -1160,16 +1116,10 @@ func easyjson7ebaa60bEncodeGithubComVungleVungoOpenrtb1(out *jwriter.Writer, in
 		out.RawString(prefix)
 		out.String(string(in.Vendor))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/metric.go b/openrtb/metric.go
index e4d73af..f887130 100644
--- a/openrtb/metric.go
+++ b/openrtb/metric.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -46,7 +47,7 @@ type Metric struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -67,6 +68,6 @@ func (m *Metric) Copy() *Metric {
 		return nil
 	}
 	mCopy := *m
-	mCopy.Ext = util.DeepCopyCopiable(m.Ext)
+	mCopy.Ext = util.DeepCopyJSONRawMsg(m.Ext)
 	return &mCopy
 }
diff --git a/openrtb/metric_easyjson.go b/openrtb/metric_easyjson.go
index 6e7d4f1..9abe315 100644
--- a/openrtb/metric_easyjson.go
+++ b/openrtb/metric_easyjson.go
@@ -43,12 +43,8 @@ func easyjson9478868cDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Me
 		case "vendor":
 			out.Vendor = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -79,16 +75,10 @@ func easyjson9478868cEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in M
 		out.RawString(prefix)
 		out.String(string(in.Vendor))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/metric_test.go b/openrtb/metric_test.go
index 606fbf6..06bf0aa 100644
--- a/openrtb/metric_test.go
+++ b/openrtb/metric_test.go
@@ -1,6 +1,7 @@
 package openrtb_test
 
 import (
+	"encoding/json"
 	"testing"
 
 	"github.com/Vungle/vungo/openrtb"
@@ -26,7 +27,7 @@ func TestMetric_Validate(t *testing.T) {
 		Type   string
 		Value  float64
 		Vendor string
-		Ext    interface{}
+		Ext    json.RawMessage
 	}
 	tests := []struct {
 		name    string
diff --git a/openrtb/native.go b/openrtb/native.go
index 06945e6..795190c 100644
--- a/openrtb/native.go
+++ b/openrtb/native.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -62,7 +63,7 @@ type Native struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -93,7 +94,7 @@ func (n *Native) Copy() *Native {
 		copy(vCopy.APIFrameworks, n.APIFrameworks)
 	}
 
-	vCopy.Extension = util.DeepCopyCopiable(n.Extension)
+	vCopy.Extension = util.DeepCopyJSONRawMsg(n.Extension)
 
 	return &vCopy
 }
diff --git a/openrtb/native/request/asset.go b/openrtb/native/request/asset.go
index 5899120..7212e6d 100644
--- a/openrtb/native/request/asset.go
+++ b/openrtb/native/request/asset.go
@@ -1,5 +1,7 @@
 package request
 
+import "encoding/json"
+
 // Asset Object is the main container object for each asset requested or supported by Exchange on behalf of the rendering client.
 // Any object that is required is to be flagged as such.
 // Only one of the {title,img,video,data} objects should be present in each object.
@@ -96,5 +98,5 @@ type Asset struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/asset_easyjson.go b/openrtb/native/request/asset_easyjson.go
index a0274cf..8a7b2b1 100644
--- a/openrtb/native/request/asset_easyjson.go
+++ b/openrtb/native/request/asset_easyjson.go
@@ -83,12 +83,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 				easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest4(in, out.Data)
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -134,16 +130,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 		out.RawString(prefix)
 		easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest4(out, *in.Data)
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -195,12 +185,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest4(in *jlexer.
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -226,16 +212,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest4(out *jwrite
 		out.RawString(prefix)
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -309,12 +289,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest3(in *jlexer.
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -372,16 +348,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest3(out *jwrite
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -438,12 +408,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest2(in *jlexer.
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -524,7 +490,7 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest2(out *jwrite
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -532,13 +498,7 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest2(out *jwrite
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -564,12 +524,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeRequest1(in *jlexer.
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -590,16 +546,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeRequest1(out *jwrite
 		out.RawString(prefix[1:])
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/data.go b/openrtb/native/request/data.go
index ac579b9..7daaa7d 100644
--- a/openrtb/native/request/data.go
+++ b/openrtb/native/request/data.go
@@ -1,6 +1,10 @@
 package request
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // Data Object is to be used for all non-core elements of the  native unit such as Brand Name, Ratings, Review Count, Stars, Download count, descriptions etc.
 // It is also generic for future  native elements not contemplated at the time of the writing of this document.
@@ -41,5 +45,5 @@ type Data struct {
 	//   object
 	// Description:
 	// This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility beyond the standard defined in this specification
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/data_easyjson.go b/openrtb/native/request/data_easyjson.go
index 733da9c..b1e99a6 100644
--- a/openrtb/native/request/data_easyjson.go
+++ b/openrtb/native/request/data_easyjson.go
@@ -42,12 +42,8 @@ func easyjson794297d0DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -73,16 +69,10 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 		out.RawString(prefix)
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/eventtracker.go b/openrtb/native/request/eventtracker.go
index 72919c9..5a5b80f 100644
--- a/openrtb/native/request/eventtracker.go
+++ b/openrtb/native/request/eventtracker.go
@@ -1,6 +1,10 @@
 package request
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // EventTracker object specifies the types of events the bidder can request to be tracked in the bid response, and which
 //types of tracking are available for each event type, and is included as an array in the request.
@@ -39,5 +43,5 @@ type EventTracker struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/eventtracker_easyjson.go b/openrtb/native/request/eventtracker_easyjson.go
index 86142c1..7de6992 100644
--- a/openrtb/native/request/eventtracker_easyjson.go
+++ b/openrtb/native/request/eventtracker_easyjson.go
@@ -63,12 +63,8 @@ func easyjson88abeb4cDecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -105,16 +101,10 @@ func easyjson88abeb4cEncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/image.go b/openrtb/native/request/image.go
index 152935d..1633f08 100644
--- a/openrtb/native/request/image.go
+++ b/openrtb/native/request/image.go
@@ -1,6 +1,10 @@
 package request
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // Image object to be used for all image elements of the Native ad such as Icons, Main Image, etc.
 // Recommended sizes and aspect ratios are included in the Image Asset Types section.
@@ -93,5 +97,5 @@ type Image struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/image_easyjson.go b/openrtb/native/request/image_easyjson.go
index 800d978..392af4f 100644
--- a/openrtb/native/request/image_easyjson.go
+++ b/openrtb/native/request/image_easyjson.go
@@ -71,12 +71,8 @@ func easyjson220accf5DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -157,7 +153,7 @@ func easyjson220accf5EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -165,13 +161,7 @@ func easyjson220accf5EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/request.go b/openrtb/native/request/request.go
index 468e7e4..7fe34b9 100644
--- a/openrtb/native/request/request.go
+++ b/openrtb/native/request/request.go
@@ -1,6 +1,10 @@
 package request
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // Request Object defines the native advertising opportunity available for bid via this bid
 // request. It will be included as a JSON-encoded string in the bid request’s imp.native field or as a
@@ -156,5 +160,5 @@ type Request struct {
 	// Description:
 	// This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility beyond
 	//the standard defined in this specification
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/request_easyjson.go b/openrtb/native/request/request_easyjson.go
index ec126f7..63e7329 100644
--- a/openrtb/native/request/request_easyjson.go
+++ b/openrtb/native/request/request_easyjson.go
@@ -57,7 +57,7 @@ func easyjson3c9d2b01DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 				in.Delim('[')
 				if out.Assets == nil {
 					if !in.IsDelim(']') {
-						out.Assets = make([]Asset, 0, 1)
+						out.Assets = make([]Asset, 0, 0)
 					} else {
 						out.Assets = []Asset{}
 					}
@@ -102,12 +102,8 @@ func easyjson3c9d2b01DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 		case "privacy":
 			out.Privacy = int8(in.Int8())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -229,16 +225,10 @@ func easyjson3c9d2b01EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 		out.RawString(prefix)
 		out.Int8(int8(in.Privacy))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/title.go b/openrtb/native/request/title.go
index b1466d8..2af805f 100644
--- a/openrtb/native/request/title.go
+++ b/openrtb/native/request/title.go
@@ -1,5 +1,7 @@
 package request
 
+import "encoding/json"
+
 // Title object is to be used for title element of the Native ad.
 //
 // See OpenRTB Native 1.2 Sec 4.3 Title Object
@@ -26,5 +28,5 @@ type Title struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/title_easyjson.go b/openrtb/native/request/title_easyjson.go
index a136b48..facfbf0 100644
--- a/openrtb/native/request/title_easyjson.go
+++ b/openrtb/native/request/title_easyjson.go
@@ -39,12 +39,8 @@ func easyjsonE7952480DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -65,16 +61,10 @@ func easyjsonE7952480EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 		out.RawString(prefix[1:])
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/request/video.go b/openrtb/native/request/video.go
index 7eff2cd..c64ae06 100644
--- a/openrtb/native/request/video.go
+++ b/openrtb/native/request/video.go
@@ -1,6 +1,10 @@
 package request
 
-import "github.com/Vungle/vungo/openrtb"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb"
+)
 
 // Video object to be used for all video elements supported in the Native Ad. This corresponds to the Video object of
 // OpenRTB. Exchange implementers can impose their own specific restrictions. Here are the required attributes of the
@@ -62,5 +66,5 @@ type Video struct {
 	// Description:
 	// This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility beyond
 	// the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/request/video_easyjson.go b/openrtb/native/request/video_easyjson.go
index f63348c..408a25d 100644
--- a/openrtb/native/request/video_easyjson.go
+++ b/openrtb/native/request/video_easyjson.go
@@ -88,12 +88,8 @@ func easyjson3c9ce8c3DecodeGithubComVungleVungoOpenrtbNativeRequest(in *jlexer.L
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -151,16 +147,10 @@ func easyjson3c9ce8c3EncodeGithubComVungleVungoOpenrtbNativeRequest(out *jwriter
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/asset.go b/openrtb/native/response/asset.go
index ab0ce71..b666479 100644
--- a/openrtb/native/response/asset.go
+++ b/openrtb/native/response/asset.go
@@ -1,5 +1,7 @@
 package response
 
+import "encoding/json"
+
 // Asset Object is the main container object for each asset requested or supported by Exchange on behalf of the
 // rendering client. Any object that is required is to be flagged as such. Only one of the {title,img,video,data}
 // objects should be present in each object. All others should be null/absent. The id is to be unique within the
@@ -98,5 +100,5 @@ type Asset struct {
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
 	//   Bidders are encouraged not to use asset.ext for exchanging text assets. Use data.ext with custom type instead.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/asset_easyjson.go b/openrtb/native/response/asset_easyjson.go
index d742a63..13b45aa 100644
--- a/openrtb/native/response/asset_easyjson.go
+++ b/openrtb/native/response/asset_easyjson.go
@@ -92,12 +92,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 				easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse5(in, out.Link)
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -179,7 +175,7 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		}
 		easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse5(out, *in.Link)
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -187,13 +183,7 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -268,12 +258,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse5(in *jlexer
 		case "fallback":
 			out.Fallback = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -313,16 +299,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse5(out *jwrit
 		out.RawString(prefix)
 		out.String(string(in.Fallback))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -352,12 +332,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse4(in *jlexer
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -399,16 +375,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse4(out *jwrit
 		}
 		out.String(string(in.Value))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -482,12 +452,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse2(in *jlexer
 		case "h":
 			out.H = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -529,16 +495,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse2(out *jwrit
 		out.RawString(prefix)
 		out.Int64(int64(in.H))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
@@ -566,12 +526,8 @@ func easyjson3b94576aDecodeGithubComVungleVungoOpenrtbNativeResponse1(in *jlexer
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -597,16 +553,10 @@ func easyjson3b94576aEncodeGithubComVungleVungoOpenrtbNativeResponse1(out *jwrit
 		out.RawString(prefix)
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/data.go b/openrtb/native/response/data.go
index 4238e74..de065e2 100644
--- a/openrtb/native/response/data.go
+++ b/openrtb/native/response/data.go
@@ -1,6 +1,10 @@
 package response
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // Data corresponds to the Data Object in the request, with the value filled in.  The Data Object is to be used for all
 // miscellaneous elements of the  native unit such as Brand Name, Ratings, Review Count, Stars, Downloads, Price count
@@ -53,5 +57,5 @@ type Data struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/data_easyjson.go b/openrtb/native/response/data_easyjson.go
index ff3a764..c76d82f 100644
--- a/openrtb/native/response/data_easyjson.go
+++ b/openrtb/native/response/data_easyjson.go
@@ -44,12 +44,8 @@ func easyjson794297d0DecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -91,16 +87,10 @@ func easyjson794297d0EncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		}
 		out.String(string(in.Value))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/eventtracker.go b/openrtb/native/response/eventtracker.go
index adabd10..10bb3b2 100644
--- a/openrtb/native/response/eventtracker.go
+++ b/openrtb/native/response/eventtracker.go
@@ -65,5 +65,5 @@ type EventTracker struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/eventtracker_easyjson.go b/openrtb/native/response/eventtracker_easyjson.go
index f5eb6b2..8fb0c18 100644
--- a/openrtb/native/response/eventtracker_easyjson.go
+++ b/openrtb/native/response/eventtracker_easyjson.go
@@ -48,12 +48,8 @@ func easyjson88abeb4cDecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 				in.AddError((out.CustomData).UnmarshalJSON(data))
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -89,16 +85,10 @@ func easyjson88abeb4cEncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		out.RawString(prefix)
 		out.Raw((in.CustomData).MarshalJSON())
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/image.go b/openrtb/native/response/image.go
index 08cadd1..3e58134 100644
--- a/openrtb/native/response/image.go
+++ b/openrtb/native/response/image.go
@@ -1,6 +1,10 @@
 package response
 
-import "github.com/Vungle/vungo/openrtb/native"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/openrtb/native"
+)
 
 // Image object to be used for all image elements of the Native ad such as Icons, Main Image, etc.
 // It is recommended that if assetsurl/dcourl is being used rather than embedded assets, that an image of each
@@ -64,5 +68,5 @@ type Image struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/image_easyjson.go b/openrtb/native/response/image_easyjson.go
index 8f175e9..4bde872 100644
--- a/openrtb/native/response/image_easyjson.go
+++ b/openrtb/native/response/image_easyjson.go
@@ -46,12 +46,8 @@ func easyjson220accf5DecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 		case "h":
 			out.H = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -93,16 +89,10 @@ func easyjson220accf5EncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		out.RawString(prefix)
 		out.Int64(int64(in.H))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/link.go b/openrtb/native/response/link.go
index 6a31590..dc043db 100644
--- a/openrtb/native/response/link.go
+++ b/openrtb/native/response/link.go
@@ -1,5 +1,7 @@
 package response
 
+import "encoding/json"
+
 // Link object is used for ‘call to action’ assets, or other links from the Native ad.
 // This Object should be associated to its peer object in the parent Asset Object or as the master link in the top level
 // Native Ad response object. When that peer object is activated (clicked) the action should take the user to the
@@ -49,5 +51,5 @@ type Link struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/link_easyjson.go b/openrtb/native/response/link_easyjson.go
index a2659f3..e1c015c 100644
--- a/openrtb/native/response/link_easyjson.go
+++ b/openrtb/native/response/link_easyjson.go
@@ -64,12 +64,8 @@ func easyjson16eb09bcDecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 		case "fallback":
 			out.Fallback = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -109,16 +105,10 @@ func easyjson16eb09bcEncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		out.RawString(prefix)
 		out.String(string(in.Fallback))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/response.go b/openrtb/native/response/response.go
index 81f4e17..2b37db9 100644
--- a/openrtb/native/response/response.go
+++ b/openrtb/native/response/response.go
@@ -1,5 +1,7 @@
 package response
 
+import "encoding/json"
+
 // Response object is the top level JSON object which identifies a native response.
 //
 // See OpenRTB Native 1.2 Sec 5.1 Native Markup Response Object
@@ -124,5 +126,5 @@ type Response struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/response_easyjson.go b/openrtb/native/response/response_easyjson.go
index 3abb6e6..7a54cd9 100644
--- a/openrtb/native/response/response_easyjson.go
+++ b/openrtb/native/response/response_easyjson.go
@@ -118,12 +118,8 @@ func easyjson6ff3ac1dDecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 		case "privacy":
 			out.Privacy = string(in.String())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -232,16 +228,10 @@ func easyjson6ff3ac1dEncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		out.RawString(prefix)
 		out.String(string(in.Privacy))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native/response/title.go b/openrtb/native/response/title.go
index 1a1b26d..cb64c33 100644
--- a/openrtb/native/response/title.go
+++ b/openrtb/native/response/title.go
@@ -1,5 +1,7 @@
 package response
 
+import "encoding/json"
+
 // Title corresponds to the Title Object in the request, with the value filled in.
 // If using assetsurl or dcourl response rather than embedded asset response, it is recommended that three title objects
 // be provided, the length of each of which is less than or equal to the three recommended maximum title lengths
@@ -39,5 +41,5 @@ type Title struct {
 	// Description:
 	//   This object is a placeholder that may contain custom JSON agreed to by the parties to support flexibility
 	//   beyond the standard defined in this specification.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
diff --git a/openrtb/native/response/title_easyjson.go b/openrtb/native/response/title_easyjson.go
index bac7b9b..473a536 100644
--- a/openrtb/native/response/title_easyjson.go
+++ b/openrtb/native/response/title_easyjson.go
@@ -41,12 +41,8 @@ func easyjsonE7952480DecodeGithubComVungleVungoOpenrtbNativeResponse(in *jlexer.
 		case "len":
 			out.Len = int64(in.Int64())
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -72,16 +68,10 @@ func easyjsonE7952480EncodeGithubComVungleVungoOpenrtbNativeResponse(out *jwrite
 		out.RawString(prefix)
 		out.Int64(int64(in.Len))
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/native_easyjson.go b/openrtb/native_easyjson.go
index 25f78f7..cba003f 100644
--- a/openrtb/native_easyjson.go
+++ b/openrtb/native_easyjson.go
@@ -87,12 +87,8 @@ func easyjson3eeb1cddDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Na
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -146,16 +142,10 @@ func easyjson3eeb1cddEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in N
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/openrtbtest/testutil.go b/openrtb/openrtbtest/testutil.go
index d53be4d..eed15d9 100644
--- a/openrtb/openrtbtest/testutil.go
+++ b/openrtb/openrtbtest/testutil.go
@@ -13,6 +13,7 @@ import (
 	"github.com/Vungle/vungo/internal/util/utiltest"
 	"github.com/Vungle/vungo/openrtb"
 	"github.com/go-test/deep"
+	"github.com/google/go-cmp/cmp"
 )
 
 // UnmarshalFromJSONFile method reads from a testdata/*.json file and unmarshals the content into
@@ -60,11 +61,8 @@ func VerifyModelAgainstFile(t Testing, file string, modelType reflect.Type) {
 		t.Fatalf("Cannot unmarshal JSON data into %v because of\n%v.", modelType, err)
 	}
 
-	if !reflect.DeepEqual(model1, model2) {
-		m1JSON, _ := json.MarshalIndent(model1, "", "  ")
-		m2JSON, _ := json.MarshalIndent(model2, "", "  ")
-		t.Logf("Unmarshaled: %s\nRe-marshaled: %s.", m1JSON, m2JSON)
-		t.Error("Unmarshaled model should be the same as re-marshaled model.")
+	if d := cmp.Diff(model1, model2); d != "" {
+		t.Errorf("Reduce() mismatch (-got +want):\n%s", d)
 	}
 
 	verifyModelNonEmptyFields(t, jsonBytes, modelType)
@@ -79,7 +77,7 @@ func verifyModelNonEmptyFields(t Testing, jsonBytes []byte, modelType reflect.Ty
 		// TODO(@garukun): Consider encapsulate pretty-printing JSON into a common library call for
 		// testing.
 		buf := bytes.NewBuffer(make([]byte, 0, len(jsonBytes)))
-		json.Indent(buf, jsonBytes, "", "  ")
+		_ = json.Indent(buf, jsonBytes, "", "  ")
 		t.Log(buf.String())
 
 		t.Fatalf("Cannot unmarshal json onto %v.\n%v", modelType, err)
@@ -197,7 +195,7 @@ func NewBidRequestForTesting(id string, impressionID string) *openrtb.BidRequest
 	return &openrtb.BidRequest{
 		ID: id,
 		Impressions: []*openrtb.Impression{
-			&openrtb.Impression{
+			{
 				ID:               impressionID,
 				BidFloorCurrency: openrtb.CurrencyUSD,
 			},
@@ -304,7 +302,7 @@ func verifyDeepCopyImpl(prefix string, src, dst reflect.Value) []string {
 	}
 	if src.CanAddr() && dst.CanAddr() && dst.Addr() == src.Addr() {
 		r = append(r, fmt.Sprintf("%v share\n\tgot  %#+v\n\twant %#+v\n",
-			prefix, dst.Addr(), src.Addr()))
+			prefix, dst.Kind().String(), src.Kind().String()))
 	}
 	switch src.Kind() {
 	case reflect.Ptr:
diff --git a/openrtb/openrtbutil/request_test.go b/openrtb/openrtbutil/request_test.go
index 20150f8..faafd72 100644
--- a/openrtb/openrtbutil/request_test.go
+++ b/openrtb/openrtbutil/request_test.go
@@ -2,7 +2,6 @@ package openrtbutil_test
 
 import (
 	"context"
-	"encoding/json"
 	"net/url"
 	"reflect"
 	"testing"
@@ -31,21 +30,6 @@ func TestNewRequestError(t *testing.T) {
 			openrtbutil.ErrEmptyURL.Error(),
 		},
 
-		// Should return JSON marshaling error.
-		{
-			&openrtb.BidRequest{
-				Application: &openrtb.Application{
-					// Fake a JSON marshaling error by creating an impossible-to-marshal value.
-					Extension: func() {},
-				},
-			},
-			"http://localhost",
-			[]reflect.Type{
-				reflect.TypeOf((*json.MarshalerError)(nil)),
-				reflect.TypeOf((*json.UnsupportedTypeError)(nil)),
-			}, // seems like diff os will report diff err type
-		},
-
 		// Should return URL parsing error.
 		{
 			&openrtb.BidRequest{},
diff --git a/openrtb/privatemarketplace.go b/openrtb/privatemarketplace.go
index ae7cfe4..6a9b2a1 100644
--- a/openrtb/privatemarketplace.go
+++ b/openrtb/privatemarketplace.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // PrivateMarketplace type contains additional metadata about an impression such that individual
 // buyers are encouraged to buy the impressions via a different channel.
@@ -8,9 +12,9 @@ import "github.com/Vungle/vungo/internal/util"
 //go:generate easyjson $GOFILE
 //easyjson:json
 type PrivateMarketplace struct {
-	IsPrivateAuction NumericBool `json:"private_auction"`
-	Deals            []*Deal     `json:"deals"`
-	Extension        interface{} `json:"ext,omitempty"`
+	IsPrivateAuction NumericBool     `json:"private_auction"`
+	Deals            []*Deal         `json:"deals"`
+	Extension        json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy returns a pointer to a copy of the Impression object.
@@ -27,6 +31,6 @@ func (pmp *PrivateMarketplace) Copy() *PrivateMarketplace {
 		}
 	}
 
-	pmpCopy.Extension = util.DeepCopyCopiable(pmp.Extension)
+	pmpCopy.Extension = util.DeepCopyJSONRawMsg(pmp.Extension)
 	return &pmpCopy
 }
diff --git a/openrtb/privatemarketplace_easyjson.go b/openrtb/privatemarketplace_easyjson.go
index f5d301f..b192423 100644
--- a/openrtb/privatemarketplace_easyjson.go
+++ b/openrtb/privatemarketplace_easyjson.go
@@ -72,12 +72,8 @@ func easyjsonE1675e4eDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Pr
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -118,16 +114,10 @@ func easyjsonE1675e4eEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in P
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/producer.go b/openrtb/producer.go
index d5531d4..151472b 100644
--- a/openrtb/producer.go
+++ b/openrtb/producer.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Producer object defines the producer of the content in which the ad will be
 // shown.
@@ -53,7 +57,7 @@ type Producer struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Site object contains required and
@@ -71,6 +75,6 @@ func (p *Producer) Copy() *Producer {
 	}
 	pCopy := *p
 	pCopy.Cat = util.DeepCopyStrSlice(p.Cat)
-	pCopy.Ext = util.DeepCopyCopiable(p.Ext)
+	pCopy.Ext = util.DeepCopyJSONRawMsg(p.Ext)
 	return &pCopy
 }
diff --git a/openrtb/producer_easyjson.go b/openrtb/producer_easyjson.go
index f77230b..c9f0d7c 100644
--- a/openrtb/producer_easyjson.go
+++ b/openrtb/producer_easyjson.go
@@ -66,12 +66,8 @@ func easyjson92a4b12aDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Pr
 		case "domain":
 			out.Domain = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -132,7 +128,7 @@ func easyjson92a4b12aEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in P
 		}
 		out.String(string(in.Domain))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -140,13 +136,7 @@ func easyjson92a4b12aEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in P
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/regulation.go b/openrtb/regulation.go
index 3cbe342..c9c062f 100644
--- a/openrtb/regulation.go
+++ b/openrtb/regulation.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Regulation types denotes any industry, legal, or governmental regulations with respect to the
 // parent bid request object.
@@ -8,8 +12,8 @@ import "github.com/Vungle/vungo/internal/util"
 //go:generate easyjson $GOFILE
 //easyjson:json
 type Regulation struct {
-	IsCoppaCompliant *NumericBool `json:"coppa,omitempty"`
-	Extension        interface{}  `json:"ext,omitempty"`
+	IsCoppaCompliant *NumericBool    `json:"coppa,omitempty"`
+	Extension        json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy returns a pointer to a copy of the Regulation object.
@@ -22,7 +26,7 @@ func (r *Regulation) Copy() *Regulation {
 		coppaCopy := *r.IsCoppaCompliant
 		regulationCopy.IsCoppaCompliant = &coppaCopy
 	}
-	regulationCopy.Extension = util.DeepCopyCopiable(r.Extension)
+	regulationCopy.Extension = util.DeepCopyJSONRawMsg(r.Extension)
 
 	return &regulationCopy
 }
diff --git a/openrtb/regulation_easyjson.go b/openrtb/regulation_easyjson.go
index e3a31b1..3a50ce9 100644
--- a/openrtb/regulation_easyjson.go
+++ b/openrtb/regulation_easyjson.go
@@ -49,12 +49,8 @@ func easyjson1db63384DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Re
 				}
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -76,7 +72,7 @@ func easyjson1db63384EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in R
 		out.RawString(prefix[1:])
 		out.Raw((*in.IsCoppaCompliant).MarshalJSON())
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -84,13 +80,7 @@ func easyjson1db63384EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in R
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/segment.go b/openrtb/segment.go
index c14d138..48f2f58 100644
--- a/openrtb/segment.go
+++ b/openrtb/segment.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Segment objects are essentially key-value pairs that convey specific units of
 // data.
@@ -43,7 +47,7 @@ type Segment struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Site object contains required and
@@ -60,6 +64,6 @@ func (s *Segment) Copy() *Segment {
 		return nil
 	}
 	sCopy := *s
-	sCopy.Ext = util.DeepCopyCopiable(s.Ext)
+	sCopy.Ext = util.DeepCopyJSONRawMsg(s.Ext)
 	return &sCopy
 }
diff --git a/openrtb/segment_easyjson.go b/openrtb/segment_easyjson.go
index 7fb159d..6a1514e 100644
--- a/openrtb/segment_easyjson.go
+++ b/openrtb/segment_easyjson.go
@@ -43,12 +43,8 @@ func easyjson88ee421DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Seg
 		case "value":
 			out.Value = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -90,7 +86,7 @@ func easyjson88ee421EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in Se
 		}
 		out.String(string(in.Value))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -98,13 +94,7 @@ func easyjson88ee421EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in Se
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/site.go b/openrtb/site.go
index 10d00b4..70ca25f 100644
--- a/openrtb/site.go
+++ b/openrtb/site.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Site object should be included if the ad supported content is a website as
 // opposed to a non-browser application.
@@ -133,7 +137,7 @@ type Site struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method checks to see if the Site object contains required and
@@ -157,6 +161,6 @@ func (s *Site) Copy() *Site {
 	sCopy.PrivacyPolicy = s.PrivacyPolicy.Copy()
 	sCopy.Publisher = s.Publisher.Copy()
 	sCopy.Content = s.Content.Copy()
-	sCopy.Ext = util.DeepCopyCopiable(s.Ext)
+	sCopy.Ext = util.DeepCopyJSONRawMsg(s.Ext)
 	return &sCopy
 }
diff --git a/openrtb/site_easyjson.go b/openrtb/site_easyjson.go
index d4718c4..fb6f68c 100644
--- a/openrtb/site_easyjson.go
+++ b/openrtb/site_easyjson.go
@@ -164,12 +164,8 @@ func easyjsonD9064c5DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Sit
 		case "keywords":
 			out.Keywords = string(in.String())
 		case "ext":
-			if m, ok := out.Ext.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Ext.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Ext = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Ext).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -348,7 +344,7 @@ func easyjsonD9064c5EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in Si
 		}
 		out.String(string(in.Keywords))
 	}
-	if in.Ext != nil {
+	if len(in.Ext) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -356,13 +352,7 @@ func easyjsonD9064c5EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in Si
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Ext.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Ext.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Ext))
-		}
+		out.Raw((in.Ext).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/source.go b/openrtb/source.go
index 0cc9429..ed68fd3 100644
--- a/openrtb/source.go
+++ b/openrtb/source.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // Source object describes the nature and behavior of the entity that is the source of the bid request upstream from the exchange.
 // The primary purpose of this object is to define post-auction or upstream decisioning when the exchange itself does not control the final decision.
@@ -40,7 +44,7 @@ type Source struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Ext interface{} `json:"ext,omitempty"`
+	Ext json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy returns a pointer to a copy of the Source object.
@@ -49,6 +53,6 @@ func (s *Source) Copy() *Source {
 		return nil
 	}
 	sourceCopy := *s
-	sourceCopy.Ext = util.DeepCopyCopiable(s.Ext)
+	sourceCopy.Ext = util.DeepCopyJSONRawMsg(s.Ext)
 	return &sourceCopy
 }
diff --git a/openrtb/testdata/bidrequest.json b/openrtb/testdata/bidrequest.json
index 06083dd..a170629 100644
--- a/openrtb/testdata/bidrequest.json
+++ b/openrtb/testdata/bidrequest.json
@@ -130,26 +130,7 @@
     "coppa": 1
   },
   "source": {
-    "ext": {
-      "schain": {
-        "ver": "1.0",
-        "complete": 1,
-        "nodes": [
-          {
-            "asi": "directseller.com",
-            "sid": "00001",
-            "rid": "BidRequest1",
-            "hp": 1
-          },
-          {
-            "asi": "reseller.com",
-            "sid": "aaaaa",
-            "rid": "BidRequest2",
-            "hp": 1
-          }
-        ]
-      }
-    }
+    "ext": {"schain":{"ver":"1.0","complete":1,"nodes":[{"asi":"directseller.com","sid":"00001","rid":"BidRequest1","hp":1},{"asi":"reseller.com","sid":"aaaaa","rid":"BidRequest2","hp":1}]}}
   },
   "ext": {}
 }
diff --git a/openrtb/testdata/regulation.json b/openrtb/testdata/regulation.json
index bd5bbca..bfa8414 100644
--- a/openrtb/testdata/regulation.json
+++ b/openrtb/testdata/regulation.json
@@ -1,6 +1 @@
-{
-  "coppa": 1,
-  "ext": {
-    "gdpr": 1
-  }
-}
+{"coppa":1,"ext":{"gdpr":1}}
diff --git a/openrtb/user.go b/openrtb/user.go
index d8e5aa8..56cfbdf 100644
--- a/openrtb/user.go
+++ b/openrtb/user.go
@@ -1,6 +1,10 @@
 package openrtb
 
-import "github.com/Vungle/vungo/internal/util"
+import (
+	"encoding/json"
+
+	"github.com/Vungle/vungo/internal/util"
+)
 
 // User type contains known or derived information about the human user of the device; i.e., the
 // audience of the audience for advertising.
@@ -9,15 +13,15 @@ import "github.com/Vungle/vungo/internal/util"
 //go:generate easyjson $GOFILE
 //easyjson:json
 type User struct {
-	ID         string      `json:"id,omitempty"`
-	BuyerID    string      `json:"buyeruid,omitempty"`
-	BirthYear  int         `json:"yob,omitempty"`
-	Gender     Gender      `json:"gender,omitempty"`
-	Keywords   string      `json:"keywords,omitempty"`
-	CustomData string      `json:"customdata,omitempty"`
-	Geo        *Geo        `json:"geo,omitempty"`
-	Data       []Data      `json:"data,omitempty"`
-	Extension  interface{} `json:"ext,omitempty"`
+	ID         string          `json:"id,omitempty"`
+	BuyerID    string          `json:"buyeruid,omitempty"`
+	BirthYear  int             `json:"yob,omitempty"`
+	Gender     Gender          `json:"gender,omitempty"`
+	Keywords   string          `json:"keywords,omitempty"`
+	CustomData string          `json:"customdata,omitempty"`
+	Geo        *Geo            `json:"geo,omitempty"`
+	Data       []Data          `json:"data,omitempty"`
+	Extension  json.RawMessage `json:"ext,omitempty"`
 }
 
 // Copy returns a pointer to a copy of the User object.
@@ -28,7 +32,7 @@ func (u *User) Copy() *User {
 	userCopy := *u
 
 	if u.Geo != nil {
-		GeoCopy := *u.Geo
+		GeoCopy := *u.Geo.Copy()
 		userCopy.Geo = &GeoCopy
 	}
 
@@ -37,7 +41,7 @@ func (u *User) Copy() *User {
 		copy(userCopy.Data, u.Data)
 	}
 
-	userCopy.Extension = util.DeepCopyCopiable(u.Extension)
+	userCopy.Extension = util.DeepCopyJSONRawMsg(u.Extension)
 
 	return &userCopy
 }
diff --git a/openrtb/user_easyjson.go b/openrtb/user_easyjson.go
index 6be1538..5bf8ce7 100644
--- a/openrtb/user_easyjson.go
+++ b/openrtb/user_easyjson.go
@@ -82,12 +82,8 @@ func easyjson9e1087fdDecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Us
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -188,7 +184,7 @@ func easyjson9e1087fdEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in U
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		if first {
 			first = false
@@ -196,13 +192,7 @@ func easyjson9e1087fdEncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in U
 		} else {
 			out.RawString(prefix)
 		}
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }
diff --git a/openrtb/video.go b/openrtb/video.go
index cb01be8..18ba488 100644
--- a/openrtb/video.go
+++ b/openrtb/video.go
@@ -1,6 +1,7 @@
 package openrtb
 
 import (
+	"encoding/json"
 	"errors"
 
 	"github.com/Vungle/vungo/internal/util"
@@ -260,7 +261,7 @@ type Video struct {
 	//   object
 	// Description:
 	//   Placeholder for exchange-specific extensions to OpenRTB.
-	Extension interface{} `json:"ext,omitempty"`
+	Extension json.RawMessage `json:"ext,omitempty"`
 }
 
 // Validate method implements a Validater interface and return a validation error according to the
@@ -325,7 +326,7 @@ func (v *Video) Copy() *Video {
 		copy(vCopy.CompanionTypes, v.CompanionTypes)
 	}
 
-	vCopy.Extension = util.DeepCopyCopiable(v.Extension)
+	vCopy.Extension = util.DeepCopyJSONRawMsg(v.Extension)
 
 	return &vCopy
 }
diff --git a/openrtb/video_easyjson.go b/openrtb/video_easyjson.go
index f52e3fc..9194cd1 100644
--- a/openrtb/video_easyjson.go
+++ b/openrtb/video_easyjson.go
@@ -283,12 +283,8 @@ func easyjson3c9ce8c3DecodeGithubComVungleVungoOpenrtb(in *jlexer.Lexer, out *Vi
 				in.Delim(']')
 			}
 		case "ext":
-			if m, ok := out.Extension.(easyjson.Unmarshaler); ok {
-				m.UnmarshalEasyJSON(in)
-			} else if m, ok := out.Extension.(json.Unmarshaler); ok {
-				_ = m.UnmarshalJSON(in.Raw())
-			} else {
-				out.Extension = in.Interface()
+			if data := in.Raw(); in.Ok() {
+				in.AddError((out.Extension).UnmarshalJSON(data))
 			}
 		default:
 			in.SkipRecursive()
@@ -508,16 +504,10 @@ func easyjson3c9ce8c3EncodeGithubComVungleVungoOpenrtb(out *jwriter.Writer, in V
 			out.RawByte(']')
 		}
 	}
-	if in.Extension != nil {
+	if len(in.Extension) != 0 {
 		const prefix string = ",\"ext\":"
 		out.RawString(prefix)
-		if m, ok := in.Extension.(easyjson.Marshaler); ok {
-			m.MarshalEasyJSON(out)
-		} else if m, ok := in.Extension.(json.Marshaler); ok {
-			out.Raw(m.MarshalJSON())
-		} else {
-			out.Raw(json.Marshal(in.Extension))
-		}
+		out.Raw((in.Extension).MarshalJSON())
 	}
 	out.RawByte('}')
 }