diff --git a/Core/src/main/kotlin/com/insanusmokrassar/postssystem/core/content/SpecialContent.kt b/Core/src/main/kotlin/com/insanusmokrassar/postssystem/core/content/SpecialContent.kt
new file mode 100644
index 00000000..58287a41
--- /dev/null
+++ b/Core/src/main/kotlin/com/insanusmokrassar/postssystem/core/content/SpecialContent.kt
@@ -0,0 +1,21 @@
+package com.insanusmokrassar.postssystem.core.content
+
+import kotlinx.serialization.Serializable
+
+interface SpecialContent : Content {
+    val internalId: ContentId
+}
+
+interface SpecialRegisteredContent : RegisteredContent, SpecialContent
+
+@Serializable
+data class SimpleSpecialContent(
+    override val internalId: ContentId
+) : SpecialContent
+
+@Serializable
+data class SimpleSpecialRegisteredContent(
+    override val id: ContentId,
+    override val internalId: ContentId
+) : SpecialRegisteredContent
+