diff --git a/codegen/generated!.gotpl b/codegen/generated!.gotpl
index 42e84b65da..ae1da002e8 100644
--- a/codegen/generated!.gotpl
+++ b/codegen/generated!.gotpl
@@ -96,10 +96,22 @@
 		resolvers  ResolverRoot
 		directives DirectiveRoot
 		complexity ComplexityRoot
+		sources []*ast.Source
+		afterUnmarshal []func(ctx context.Context, obj interface{}, value interface{}) error
 	}
 
+	func (es *executableSchema) afterUnmarshalInput(ctx context.Context, obj interface{}, value interface{}) error {
+		for _, fn := range es.afterUnmarshal {
+			if err := fn(ctx, obj, value); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+
 	func (e *executableSchema) Schema() *ast.Schema {
-		return parsedSchema
+		return gqlparser.MustLoadSchema(e.sources...)
 	}
 
 	func (e *executableSchema) Complexity(typeName, field string, childComplexity int, rawArgs map[string]interface{}) (int, bool) {
diff --git a/codegen/input.gotpl b/codegen/input.gotpl
index 126ff661c3..dcd125399a 100644
--- a/codegen/input.gotpl
+++ b/codegen/input.gotpl
@@ -88,7 +88,8 @@
 			}
 		}
 
-		return {{$it}}, nil
+		err := ec.afterUnmarshalInput(ctx, &{{$it}}, obj)
+		return {{$it}}, err
 	}
 	{{- end }}
 {{ end }}
diff --git a/codegen/root_.gotpl b/codegen/root_.gotpl
index dcfc84d0ed..e1cfa1cf0a 100644
--- a/codegen/root_.gotpl
+++ b/codegen/root_.gotpl
@@ -20,6 +20,7 @@ func NewExecutableSchema(cfg Config) graphql.ExecutableSchema {
 		resolvers: cfg.Resolvers,
 		directives: cfg.Directives,
 		complexity: cfg.Complexity,
+		sources: sources,
 	}
 }
 
@@ -69,10 +70,20 @@ type executableSchema struct {
 	resolvers  ResolverRoot
 	directives DirectiveRoot
 	complexity ComplexityRoot
+	sources []*ast.Source
+	afterUnmarshal []func(ctx context.Context, obj interface{}, value interface{}) error
 }
 
+func (es *executableSchema) afterUnmarshalInput(ctx context.Context, obj interface{}, value interface{}) error {
+	for _, fn := range es.afterUnmarshal {
+		if err := fn(ctx, obj, value); err != nil {
+			return err
+		}
+	}
+	return nil
+}
 func (e *executableSchema) Schema() *ast.Schema {
-	return parsedSchema
+	return gqlparser.MustLoadSchema(e.sources...)
 }
 
 func (e *executableSchema) Complexity(typeName, field string, childComplexity int, rawArgs map[string]interface{}) (int, bool) {
@@ -270,4 +281,4 @@ var sources = []*ast.Source{
 	{Name: {{$source.RelativePath|quote}}, Input: {{if (not $source.Embeddable)}}{{$source.Source|rawQuote}}{{else}}sourceData({{$source.RelativePath|quote}}){{end}}, BuiltIn: {{$source.BuiltIn}}},
 {{- end }}
 }
-var parsedSchema = gqlparser.MustLoadSchema(sources...)
+// var parsedSchema = gqlparser.MustLoadSchema(sources...)
diff --git a/plugin/federation/federation.gotpl b/plugin/federation/federation.gotpl
index 7cf84287eb..1fc3539c9b 100644
--- a/plugin/federation/federation.gotpl
+++ b/plugin/federation/federation.gotpl
@@ -18,7 +18,7 @@ func (ec *executionContext) __resolve__service(ctx context.Context) (fedruntime.
 
 	var sdl []string
 
-	for _, src := range sources {
+	for _, src := range ec.sources {
 		if src.BuiltIn {
 			continue
 		}