diff --git a/upub/core/src/traits/process.rs b/upub/core/src/traits/process.rs
index a55158f..2cf549e 100644
--- a/upub/core/src/traits/process.rs
+++ b/upub/core/src/traits/process.rs
@@ -60,16 +60,24 @@ pub async fn create(ctx: &crate::Context, activity: impl apb::Activity, tx: &Dat
 		tracing::error!("refusing to process activity without embedded object");
 		return Err(ProcessorError::Unprocessable);
 	};
-	if let Ok(reply) = object_node.in_reply_to().id() {
-		if let Err(e) = ctx.fetch_object(reply, tx).await {
-			tracing::warn!("failed fetching replies for received object: {e}");
-		}
-	}
+	let oid = object_node.id()?.to_string();
+	let addressed = object_node.addressed();
 	let activity_model = ctx.insert_activity(activity, tx).await?;
-	let object_model = ctx.insert_object(object_node, tx).await?;
-	let expanded_addressing = ctx.expand_addressing(object_model.addressed()).await?;
-	ctx.address_to(Some(activity_model.internal), Some(object_model.internal), &expanded_addressing, tx).await?;
-	tracing::info!("{} posted {}", activity_model.actor, object_model.id);
+	let internal_oid = if let Some(internal) = model::object::Entity::ap_to_internal(&oid, tx).await? {
+		tracing::debug!("skipping insertion of already known object #{internal}");
+		internal
+	} else {
+		if let Ok(reply) = object_node.in_reply_to().id() {
+			if let Err(e) = ctx.fetch_object(reply, tx).await {
+				tracing::warn!("failed fetching replies for received object: {e}");
+			}
+		}
+		let object_model = ctx.insert_object(object_node, tx).await?;
+		object_model.internal
+	};
+	let expanded_addressing = ctx.expand_addressing(addressed).await?;
+	ctx.address_to(Some(activity_model.internal), Some(internal_oid), &expanded_addressing, tx).await?;
+	tracing::info!("{} posted {}", activity_model.actor, oid);
 	Ok(())
 }