diff --git a/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/api/MutablePostsAPI.kt b/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/api/MutablePostsAPI.kt
new file mode 100644
index 00000000..847c527f
--- /dev/null
+++ b/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/api/MutablePostsAPI.kt
@@ -0,0 +1,15 @@
+package com.github.insanusmokrassar.postssystem.core.api
+
+import com.github.insanusmokrassar.postssystem.core.post.*
+import kotlinx.coroutines.flow.Flow
+
+interface MutablePostsAPI {
+    val postCreatedFlow: Flow<Post>
+    val postDeletedFlow: Flow<Post>
+    val postUpdatedFlow: Flow<Post>
+
+    suspend fun createPost(content: PostContents): Post?
+    suspend fun deletePost(id: PostId): Boolean
+
+    suspend fun updatePostContent(postId: PostId, content: PostContents): Boolean
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/Post.kt b/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/Post.kt
index 08a0e98f..82588238 100644
--- a/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/Post.kt
+++ b/src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/Post.kt
@@ -3,10 +3,11 @@ package com.github.insanusmokrassar.postssystem.core.post
 import com.github.insanusmokrassar.postssystem.core.content.Content
 
 typealias PostId = String
+typealias PostContents = List<Content>
 
 interface Post {
     val id: PostId
-    val content: List<Content>
+    val content: PostContents
 
     val meta: PostMetaInfo
 }
\ No newline at end of file