diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index db8a466..8d69b04 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -1,2 +1,5 @@
 # Scala Steward: Reformat with scalafmt 3.6.1
 122bd2ff9365edaae9ecf907e8b25ae07e6a761e
+
+# Scala Steward: Reformat with scalafmt 3.9.9
+c0a146029e44349293b77bef42054a788e473dc0
diff --git a/.scalafmt.conf b/.scalafmt.conf
index d7f45d6..259ede9 100644
--- a/.scalafmt.conf
+++ b/.scalafmt.conf
@@ -20,7 +20,7 @@ rewrite.rules = [RedundantParens]
 runner.dialect = scala213
 spaces.inImportCurlyBraces = false
 trailingCommas = "always"
-version = "3.6.1"
+version = "3.9.9"
 
 align.tokens."+" = [
     {code = "->>"  }
diff --git a/build.sbt b/build.sbt
index 11e9d65..9c80a05 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,17 +1,17 @@
 import Dependencies._
 
 // Flags
-Global / semanticdbEnabled        := true
-Global / onChangedBuildSource     := ReloadOnSourceChanges
-Global / scalacOptions            := Seq(
+Global / semanticdbEnabled             := true
+Global / onChangedBuildSource          := ReloadOnSourceChanges
+Global / scalacOptions                 := Seq(
   "-Ywarn-unused",
   "-Werror",
   "-feature",
   "-language:reflectiveCalls",
   "-deprecation",
 )
-Global / scalaVersion             := "2.13.8"
-ThisBuild / versionScheme         := Some("early-semver")
+Global / scalaVersion                  := "2.13.8"
+ThisBuild / versionScheme              := Some("early-semver")
 ThisBuild / testFrameworks += new TestFramework("zio.test.sbt.ZTestFramework")
 ThisBuild / githubWorkflowJavaVersions := Seq(JavaSpec.temurin("11"))
 ThisBuild / githubWorkflowTargetTags ++= Seq("v*")
@@ -77,6 +77,6 @@ lazy val zioComposeGraphQL = project.in(file("./compose-graphql"))
       ZIOTest,
       ZIOTestSbt,
       PPrint,
-      Caliban
+      Caliban,
     ),
   )
diff --git a/compose-graphql/src/main/scala/compose/graphql/StepGenerator.scala b/compose-graphql/src/main/scala/compose/graphql/StepGenerator.scala
index fe7f81b..b6e2242 100644
--- a/compose-graphql/src/main/scala/compose/graphql/StepGenerator.scala
+++ b/compose-graphql/src/main/scala/compose/graphql/StepGenerator.scala
@@ -77,7 +77,7 @@ final class StepGenerator(graph: Graph, i: Interpreter) {
       // case MetaSchema.FailNode(message, path, optional)        => ???
       // case MetaSchema.Either(path, left, right, optional)      => ???
       // case MetaSchema.Sum(id, path, cases, optional)           => ???
-      case schema                            => throw new MatchError(schema)
+      case schema => throw new MatchError(schema)
     }
 
   }
diff --git a/compose-graphql/src/main/scala/compose/graphql/TypeGenerator.scala b/compose-graphql/src/main/scala/compose/graphql/TypeGenerator.scala
index da72136..ef60f0f 100644
--- a/compose-graphql/src/main/scala/compose/graphql/TypeGenerator.scala
+++ b/compose-graphql/src/main/scala/compose/graphql/TypeGenerator.scala
@@ -62,7 +62,7 @@ final class TypeGenerator(graph: Graph) {
     }.foreach { case (id, cons) =>
       pending.get(id) match {
         case None        => pending += (id -> cons)
-        case Some(value) => pending += id  -> (value ++ cons)
+        case Some(value) => pending += id -> (value ++ cons)
       }
     }