diff --git a/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfiguration.java b/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfiguration.java
new file mode 100644
index 0000000..550ea2f
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfiguration.java
@@ -0,0 +1,50 @@
+package de.sample.schulung.spring.blog.boundary.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.servlet.config.annotation.CorsRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+import static java.util.Arrays.stream;
+
+@SuppressWarnings("NullableProblems")
+@Configuration
+public class CorsConfiguration {
+
+    @Bean
+    public WebMvcConfigurer corsConfigurer(final CorsConfigurationData allowed) {
+        return new WebMvcConfigurer() {
+
+            @Override
+            public void addCorsMappings(final CorsRegistry registry) {
+                registry.addMapping("/**")
+                  .exposedHeaders(
+                    HttpHeaders.LOCATION,
+                    HttpHeaders.LINK
+                  )
+                  // allow all HTTP request methods
+                  .allowedMethods(
+                    stream(RequestMethod.values())
+                      .map(Enum::name)
+                      .toArray(String[]::new)
+                  )
+                  // allow the commonly used headers
+                  .allowedHeaders(
+                    HttpHeaders.ORIGIN,
+                    HttpHeaders.CONTENT_TYPE,
+                    HttpHeaders.CONTENT_LANGUAGE,
+                    HttpHeaders.ACCEPT,
+                    HttpHeaders.ACCEPT_LANGUAGE,
+                    HttpHeaders.IF_MATCH,
+                    HttpHeaders.IF_NONE_MATCH
+                  )
+                  // this is stage specific
+                  .allowedOrigins(allowed.getOrigins())
+                  .allowCredentials(allowed.isCredentials());
+            }
+        };
+    }
+
+}
diff --git a/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfigurationData.java b/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfigurationData.java
new file mode 100644
index 0000000..4a8cdc6
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/boundary/config/CorsConfigurationData.java
@@ -0,0 +1,25 @@
+package de.sample.schulung.spring.blog.boundary.config;
+
+import lombok.Data;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * The properties from application.yml. You can specify them by the following snippet:
+ *
+ * <pre>
+ * server:
+ *   endpoints:
+ *     api:
+ *       v1: /api/v1
+ * </pre>
+ */
+@Configuration
+@ConfigurationProperties(prefix = "cors.allow")
+@Data
+public class CorsConfigurationData {
+
+    private String[] origins = { "*" };
+    private boolean credentials = false;
+
+}
diff --git a/src/main/java/de/sample/schulung/spring/blog/boundary/config/IndexPageConfiguration.java b/src/main/java/de/sample/schulung/spring/blog/boundary/config/IndexPageConfiguration.java
new file mode 100644
index 0000000..f6c65a8
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/boundary/config/IndexPageConfiguration.java
@@ -0,0 +1,24 @@
+package de.sample.schulung.spring.blog.boundary.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@SuppressWarnings("NullableProblems")
+@Configuration
+public class IndexPageConfiguration {
+
+  @Bean
+  WebMvcConfigurer indexPageConfig() {
+    return new WebMvcConfigurer() {
+      @Override
+      public void addViewControllers(ViewControllerRegistry registry) {
+        registry
+          .addViewController("/")
+          .setViewName("redirect:/index.html");
+      }
+    };
+  }
+
+}
diff --git a/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostService.java b/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostService.java
index ef3f880..b3b055f 100644
--- a/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostService.java
+++ b/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostService.java
@@ -7,9 +7,6 @@
 import org.springframework.stereotype.Service;
 import org.springframework.validation.annotation.Validated;
 
-import java.time.LocalDateTime;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.stream.Stream;
@@ -19,28 +16,23 @@
 @RequiredArgsConstructor
 public class BlogPostService {
 
-  private final Map<UUID, BlogPost> blogPosts = new HashMap<>();
   private final ApplicationEventPublisher eventPublisher;
+  private final BlogPostSink sink;
 
   public long count() {
-    return blogPosts.size();
+    return sink.count();
   }
 
   public Stream<BlogPost> findAll() {
-    return blogPosts.values().stream();
+    return sink.findAll();
   }
 
   public Optional<BlogPost> findById(UUID id) {
-    return Optional.ofNullable(
-      this.blogPosts.get(id)
-    );
+    return sink.findById(id);
   }
 
   public void create(@Valid @NotNull BlogPost blogPost) {
-    final var id = UUID.randomUUID();
-    blogPost.setId(id);
-    blogPost.setTimestamp(LocalDateTime.now());
-    this.blogPosts.put(id, blogPost);
+    this.sink.create(blogPost);
     this.eventPublisher.publishEvent(new BlogPostCreatedEvent(blogPost));
   }
 
diff --git a/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostSink.java b/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostSink.java
new file mode 100644
index 0000000..ea67490
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/domain/BlogPostSink.java
@@ -0,0 +1,14 @@
+package de.sample.schulung.spring.blog.domain;
+
+import java.util.Optional;
+import java.util.UUID;
+import java.util.stream.Stream;
+
+public interface BlogPostSink {
+
+  long count();
+  void create(BlogPost post);
+  Stream<BlogPost> findAll();
+  Optional<BlogPost> findById(UUID id);
+
+}
diff --git a/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSink.java b/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSink.java
new file mode 100644
index 0000000..5c16961
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSink.java
@@ -0,0 +1,39 @@
+package de.sample.schulung.spring.blog.domain;
+
+import java.time.LocalDateTime;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.stream.Stream;
+
+public class InMemoryBlogPostSink implements BlogPostSink {
+
+  private final Map<UUID, BlogPost> blogPosts = new HashMap<>();
+
+  @Override
+  public long count() {
+    return this.blogPosts.size();
+  }
+
+  @Override
+  public void create(BlogPost post) {
+    final var id = UUID.randomUUID();
+    post.setId(id);
+    post.setTimestamp(LocalDateTime.now());
+    this.blogPosts.put(id, post);
+
+  }
+
+  @Override
+  public Stream<BlogPost> findAll() {
+    return blogPosts.values().stream();
+  }
+
+  @Override
+  public Optional<BlogPost> findById(UUID id) {
+    return Optional.ofNullable(
+      this.blogPosts.get(id)
+    );
+  }
+}
diff --git a/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSinkConfiguration.java b/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSinkConfiguration.java
new file mode 100644
index 0000000..715733c
--- /dev/null
+++ b/src/main/java/de/sample/schulung/spring/blog/domain/InMemoryBlogPostSinkConfiguration.java
@@ -0,0 +1,16 @@
+package de.sample.schulung.spring.blog.domain;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class InMemoryBlogPostSinkConfiguration {
+
+  @Bean
+  @ConditionalOnMissingBean(BlogPostSink.class)
+  BlogPostSink inMemorySink() {
+    return new InMemoryBlogPostSink();
+  }
+
+}
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index ee3322d..2b99f98 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -7,5 +7,6 @@ application:
         content: This is a great blog :)
       - title: BlogPost 2
         content: Das ist ein weiterer Blog Post
-
-
+cors:
+  allow:
+    origins: ${CORS_ALLOW_ORIGINS:*}
diff --git a/src/test/java/de/sample/schulung/spring/blog/boundary/BlogPostControllerTests.java b/src/test/java/de/sample/schulung/spring/blog/boundary/BlogPostControllerTests.java
index 1100257..03c433a 100644
--- a/src/test/java/de/sample/schulung/spring/blog/boundary/BlogPostControllerTests.java
+++ b/src/test/java/de/sample/schulung/spring/blog/boundary/BlogPostControllerTests.java
@@ -1,6 +1,7 @@
 package de.sample.schulung.spring.blog.boundary;
 
 import de.sample.schulung.spring.blog.domain.BlogPostService;
+import de.sample.schulung.spring.blog.domain.InMemoryBlogPostSink;
 import org.junit.jupiter.api.Test;
 import org.mapstruct.factory.Mappers;
 import org.mockito.Mockito;
@@ -14,7 +15,7 @@ public class BlogPostControllerTests {
   @Test
   void shouldCreateBlogPostSuccessfully() {
     final var eventPublisher = Mockito.mock(ApplicationEventPublisher.class);
-    final var service = new BlogPostService(eventPublisher);
+    final var service = new BlogPostService(eventPublisher, new InMemoryBlogPostSink());
     final var mapper = Mappers.getMapper(BlogPostDtoMapper.class);
     final var controller = new BlogPostController(service, mapper);
     final var blogPost = new BlogPostDto();