diff --git a/spring-graphql-docs/src/docs/asciidoc/index.adoc b/spring-graphql-docs/src/docs/asciidoc/index.adoc
index ce61a824..6a0e271b 100644
--- a/spring-graphql-docs/src/docs/asciidoc/index.adoc
+++ b/spring-graphql-docs/src/docs/asciidoc/index.adoc
@@ -256,6 +256,9 @@ You can use `RuntimeWiringConfigurer` to register:
    `AnnotatedControllerConfigurer`, which detects annotated, `DataFetcher` handler methods.
    The Spring Boot starter adds the `AnnotatedControllerConfigurer` by default.
 
+NOTE: Unlike web frameworks, GraphQL does not use Jackson annotations to drive JSON serialization/deserialization.
+Custom data types and their serialization https://www.graphql-java.com/documentation/scalars/[must be described as Scalars].
+
 The Spring Boot starter detects beans of type `RuntimeWiringConfigurer` and
 registers them in the `GraphQlSource.Builder`. That means in most cases, you'll' have
 something like the following in your configuration: