diff --git a/Sources/Shared/Toolkit/Format/Sniffers/AudioFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/AudioFormatSniffer.swift
index 537622a7f..f6e076539 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/AudioFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/AudioFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs audio formats.
 public class AudioFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if hints.hasFileExtension("aac") || hints.hasMediaType("audio/aac") {
             return Format(specifications: .aac, mediaType: .aac, fileExtension: "aac")
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/BitmapFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/BitmapFormatSniffer.swift
index 194d6f384..6e25c9a01 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/BitmapFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/BitmapFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs bitmap formats.
 public class BitmapFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if hints.hasFileExtension("avif", "avifs") || hints.hasMediaType("image/avif") {
             return Format(specifications: .avif, mediaType: .avif, fileExtension: "avif")
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/HTMLFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/HTMLFormatSniffer.swift
index cde72e9eb..db622f859 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/HTMLFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/HTMLFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs an HTML or XHTML document.
 public struct HTMLFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("htm", "html") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/JSONFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/JSONFormatSniffer.swift
index 5668d09ea..7505e7b0f 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/JSONFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/JSONFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs a JSON document.
 public struct JSONFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("json") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/LCPLicenseFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/LCPLicenseFormatSniffer.swift
index 5afacb3f9..dd4173524 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/LCPLicenseFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/LCPLicenseFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs an LCP License Document.
 public struct LCPLicenseFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("lcpl") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/LanguageFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/LanguageFormatSniffer.swift
index 969411a85..b401d23ab 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/LanguageFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/LanguageFormatSniffer.swift
@@ -7,6 +7,8 @@
 import Foundation
 
 public class LanguageFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         // JavaScript
         if
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/OPDSFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/OPDSFormatSniffer.swift
index 4394c9ca7..e697a6b7f 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/OPDSFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/OPDSFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs OPDS documents.
 public class OPDSFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if hints.hasMediaType("application/atom+xml;type=entry;profile=opds-catalog") {
             return opds1Entry
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/PDFFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/PDFFormatSniffer.swift
index a3626c570..7c3560811 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/PDFFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/PDFFormatSniffer.swift
@@ -10,6 +10,8 @@ import Foundation
 ///
 /// Reference: https://www.loc.gov/preservation/digital/formats/fdd/fdd000123.shtml
 public struct PDFFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("pdf") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/RARFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/RARFormatSniffer.swift
index ac2edcf62..a42498be0 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/RARFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/RARFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs a RAR file.
 public struct RARFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("rar") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/RPFFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/RPFFormatSniffer.swift
index da5dd45f1..6cb93addb 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/RPFFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/RPFFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs a Readium Web Publication package.
 public struct RPFFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if hints.hasMediaType("application/audiobook+zip") || hints.hasFileExtension("audiobook") {
             return audiobook
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/RWPMFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/RWPMFormatSniffer.swift
index 189546f16..dfb1db8e6 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/RWPMFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/RWPMFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs a Readium Web Publication Manifest.
 public struct RWPMFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if hints.hasMediaType("application/webpub+json") {
             return webpub
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/XMLFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/XMLFormatSniffer.swift
index b05584fe6..6717a551d 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/XMLFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/XMLFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs an XML document.
 public struct XMLFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("xml") ||
diff --git a/Sources/Shared/Toolkit/Format/Sniffers/ZIPFormatSniffer.swift b/Sources/Shared/Toolkit/Format/Sniffers/ZIPFormatSniffer.swift
index 045235c0f..708cf1c36 100644
--- a/Sources/Shared/Toolkit/Format/Sniffers/ZIPFormatSniffer.swift
+++ b/Sources/Shared/Toolkit/Format/Sniffers/ZIPFormatSniffer.swift
@@ -8,6 +8,8 @@ import Foundation
 
 /// Sniffs a ZIP file.
 public struct ZIPFormatSniffer: FormatSniffer {
+    public init() {}
+
     public func sniffHints(_ hints: FormatHints) -> Format? {
         if
             hints.hasFileExtension("zip") ||