diff --git a/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQLVoidScalar.java b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQLVoidScalar.java
new file mode 100644
index 0000000000..0ff1721c13
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQLVoidScalar.java
@@ -0,0 +1,30 @@
+package com.baeldung.returnnull;
+
+import graphql.schema.Coercing;
+import graphql.schema.GraphQLScalarType;
+
+public class GraphQLVoidScalar {
+
+    public static final GraphQLScalarType Void = GraphQLScalarType.newScalar()
+      .name("Void")
+      .description("A custom scalar that represents the null value")
+      .coercing(new Coercing() {
+
+          @Override
+          public Object serialize(Object dataFetcherResult) {
+              return null;
+          }
+
+          @Override
+          public Object parseValue(Object input) {
+              return null;
+          }
+
+          @Override
+          public Object parseLiteral(Object input) {
+              return null;
+          }
+      })
+      .build();
+
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQlConfig.java b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQlConfig.java
new file mode 100644
index 0000000000..3ba508eb90
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/GraphQlConfig.java
@@ -0,0 +1,14 @@
+package com.baeldung.returnnull;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.graphql.execution.RuntimeWiringConfigurer;
+
+@Configuration
+public class GraphQlConfig {
+
+    @Bean
+    public RuntimeWiringConfigurer runtimeWiringConfigurer() {
+        return wiringBuilder -> wiringBuilder.scalar(GraphQLVoidScalar.Void);
+    }
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/Post.java b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/Post.java
new file mode 100644
index 0000000000..e882bf6621
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/Post.java
@@ -0,0 +1,51 @@
+package com.baeldung.returnnull;
+
+public class Post {
+
+    private String id;
+    private String title;
+    private String text;
+    private String category;
+    private String author;
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public String getCategory() {
+        return category;
+    }
+
+    public void setCategory(String category) {
+        this.category = category;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/PostController.java b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/PostController.java
new file mode 100644
index 0000000000..99ce33c230
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/PostController.java
@@ -0,0 +1,28 @@
+package com.baeldung.returnnull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+
+import org.springframework.graphql.data.method.annotation.Argument;
+import org.springframework.graphql.data.method.annotation.MutationMapping;
+import org.springframework.stereotype.Controller;
+
+@Controller
+public class PostController {
+
+    List<Post> posts = new ArrayList<>();
+
+    @MutationMapping
+    public Void createPostReturnCustomScalar(@Argument String title, @Argument String text, @Argument String category, @Argument String author) {
+        Post post = new Post();
+        post.setId(UUID.randomUUID()
+          .toString());
+        post.setTitle(title);
+        post.setText(text);
+        post.setCategory(category);
+        post.setAuthor(author);
+        posts.add(post);
+        return null;
+    }
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/ReturnNullApp.java b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/ReturnNullApp.java
new file mode 100644
index 0000000000..7e24b0d9d7
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/java/com/baeldung/returnnull/ReturnNullApp.java
@@ -0,0 +1,14 @@
+package com.baeldung.returnnull;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ReturnNullApp {
+
+    public static void main(String[] args) {
+        System.setProperty("spring.profiles.default", "returnnull");
+        SpringApplication.run(com.baeldung.chooseapi.ChooseApiApp.class, args);
+    }
+}
+
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/resources/application-returnnull.yml b/spring-boot-modules/spring-boot-graphql/src/main/resources/application-returnnull.yml
new file mode 100644
index 0000000000..eabd906273
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/resources/application-returnnull.yml
@@ -0,0 +1,9 @@
+server:
+  port: 8082
+
+spring:
+  graphql:
+    graphiql:
+      enabled: true
+    schema:
+      locations: classpath:returnnull/
diff --git a/spring-boot-modules/spring-boot-graphql/src/main/resources/returnnull/returnnull.graphqls b/spring-boot-modules/spring-boot-graphql/src/main/resources/returnnull/returnnull.graphqls
new file mode 100644
index 0000000000..2cdff0878e
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/main/resources/returnnull/returnnull.graphqls
@@ -0,0 +1,18 @@
+scalar Void
+
+type Mutation {
+    createPostReturnNullableType(title: String!, text: String!, category: String!, author: String!) : Int
+    createPostReturnCustomScalar(title: String!, text: String!, category: String!, author: String!) : Void
+}
+
+type Post {
+    id: ID
+    title: String
+    text: String
+    category: String
+    author: String
+}
+
+type Query {
+    recentPosts(count: Int, offset: Int): [Post]!
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/test/java/com/baeldung/returnnull/PostControllerIntegrationTest.java b/spring-boot-modules/spring-boot-graphql/src/test/java/com/baeldung/returnnull/PostControllerIntegrationTest.java
new file mode 100644
index 0000000000..4d9dad0b40
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/test/java/com/baeldung/returnnull/PostControllerIntegrationTest.java
@@ -0,0 +1,48 @@
+package com.baeldung.returnnull;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.graphql.GraphQlTest;
+import org.springframework.context.annotation.Import;
+import org.springframework.graphql.test.tester.GraphQlTester;
+import org.springframework.test.context.ActiveProfiles;
+
+@GraphQlTest(PostController.class)
+@ActiveProfiles("returnnull")
+@Import(GraphQlConfig.class)
+class PostControllerIntegrationTest {
+
+    @Autowired
+    private GraphQlTester graphQlTester;
+
+    @Test
+    void givenNewPostData_whenExecuteMutation_thenReturnCustomNullScalar() {
+        String documentName = "create_post_return_custom_scalar";
+
+        graphQlTester.documentName(documentName)
+          .variable("title", "New Post")
+          .variable("text", "New post text")
+          .variable("category", "category")
+          .variable("author", "Alex")
+          .execute()
+          .path("createPostReturnCustomScalar")
+          .valueIsNull();
+
+    }
+
+    @Test
+    void givenNewPostData_whenExecuteMutation_thenReturnNullType() {
+        String documentName = "create_post_return_nullable_type";
+
+        graphQlTester.documentName(documentName)
+          .variable("title", "New Post")
+          .variable("text", "New post text")
+          .variable("category", "category")
+          .variable("author", "Alex")
+          .execute()
+          .path("createPostReturnNullableType")
+          .valueIsNull();
+
+    }
+
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_custom_scalar.graphql b/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_custom_scalar.graphql
new file mode 100644
index 0000000000..9400903ce1
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_custom_scalar.graphql
@@ -0,0 +1,3 @@
+mutation createPostReturnCustomScalar($title: String!, $text: String!, $category: String!, $author: String!) {
+    createPostReturnCustomScalar(title: $title, text: $text, category: $category, author: $author)
+}
diff --git a/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_nullable_type.graphql b/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_nullable_type.graphql
new file mode 100644
index 0000000000..f43c9bddf9
--- /dev/null
+++ b/spring-boot-modules/spring-boot-graphql/src/test/resources/graphql-test/create_post_return_nullable_type.graphql
@@ -0,0 +1,3 @@
+mutation createPostReturnNullableType($title: String!, $text: String!, $category: String!, $author: String!) {
+    createPostReturnNullableType(title: $title, text: $text, category: $category, author: $author)
+}