diff --git a/migrations/V0007__post__add_object_id.sql b/migrations/V0007__post__add_object_id.sql
new file mode 100644
index 0000000..15638c6
--- /dev/null
+++ b/migrations/V0007__post__add_object_id.sql
@@ -0,0 +1 @@
+ALTER TABLE post ADD COLUMN object_id VARCHAR(200) UNIQUE;
diff --git a/migrations/schema.sql b/migrations/schema.sql
index 456b7f9..d775015 100644
--- a/migrations/schema.sql
+++ b/migrations/schema.sql
@@ -35,6 +35,7 @@ CREATE TABLE post (
     content TEXT NOT NULL,
     in_reply_to_id UUID REFERENCES post (id) ON DELETE CASCADE,
     reply_count INTEGER NOT NULL CHECK (reply_count >= 0) DEFAULT 0,
+    object_id VARCHAR(200) UNIQUE,
     ipfs_cid VARCHAR(200),
     token_id INTEGER,
     token_tx_id VARCHAR(200),
diff --git a/src/activitypub/activity.rs b/src/activitypub/activity.rs
index ecd58b7..8e2503f 100644
--- a/src/activitypub/activity.rs
+++ b/src/activitypub/activity.rs
@@ -127,7 +127,7 @@ pub fn create_note(
             let post = in_reply_to.unwrap();
             assert_eq!(post.id, in_reply_to_id);
             match post.author.is_local() {
-                false => None, // TODO: store object ID for remote posts
+                false => post.object_id.clone(),
                 true => Some(get_object_url(&config.instance_url(), &post.id)),
             }
         },
diff --git a/src/activitypub/receiver.rs b/src/activitypub/receiver.rs
index b8f8992..670ac22 100644
--- a/src/activitypub/receiver.rs
+++ b/src/activitypub/receiver.rs
@@ -125,6 +125,7 @@ pub async fn receive_activity(
                 // TODO: parse inReplyTo field
                 in_reply_to_id: None,
                 attachments: attachments,
+                object_id: Some(object.id),
                 created_at: object.published,
             };
             create_post(db_client, &author.id, post_data).await?;
diff --git a/src/mastodon_api/statuses/types.rs b/src/mastodon_api/statuses/types.rs
index 7968f23..5e470f9 100644
--- a/src/mastodon_api/statuses/types.rs
+++ b/src/mastodon_api/statuses/types.rs
@@ -62,6 +62,7 @@ impl From<StatusData> for PostCreateData {
             content: value.status,
             in_reply_to_id: value.in_reply_to_id,
             attachments: value.media_ids.unwrap_or(vec![]),
+            object_id: None,
             created_at: None,
         }
     }
diff --git a/src/models/posts/queries.rs b/src/models/posts/queries.rs
index 7f33c36..b8bccaa 100644
--- a/src/models/posts/queries.rs
+++ b/src/models/posts/queries.rs
@@ -133,6 +133,7 @@ pub async fn create_post(
         in_reply_to_id: db_post.in_reply_to_id,
         reply_count: db_post.reply_count,
         attachments: db_attachments,
+        object_id: db_post.object_id,
         ipfs_cid: db_post.ipfs_cid,
         token_id: db_post.token_id,
         token_tx_id: db_post.token_tx_id,
diff --git a/src/models/posts/types.rs b/src/models/posts/types.rs
index a5e4230..f0f7159 100644
--- a/src/models/posts/types.rs
+++ b/src/models/posts/types.rs
@@ -18,6 +18,7 @@ pub struct DbPost {
     pub content: String,
     pub in_reply_to_id: Option<Uuid>,
     pub reply_count: i32,
+    pub object_id: Option<String>,
     pub ipfs_cid: Option<String>,
     pub token_id: Option<i32>,
     pub token_tx_id: Option<String>,
@@ -32,6 +33,7 @@ pub struct Post {
     pub in_reply_to_id: Option<Uuid>,
     pub reply_count: i32,
     pub attachments: Vec<DbMediaAttachment>,
+    pub object_id: Option<String>,
     pub ipfs_cid: Option<String>,
     pub token_id: Option<i32>,
     pub token_tx_id: Option<String>,
@@ -53,6 +55,7 @@ impl TryFrom<&Row> for Post {
             in_reply_to_id: db_post.in_reply_to_id,
             reply_count: db_post.reply_count,
             attachments: db_attachments,
+            object_id: db_post.object_id,
             ipfs_cid: db_post.ipfs_cid,
             token_id: db_post.token_id,
             token_tx_id: db_post.token_tx_id,
@@ -66,6 +69,7 @@ pub struct PostCreateData {
     pub content: String,
     pub in_reply_to_id: Option<Uuid>,
     pub attachments: Vec<Uuid>,
+    pub object_id: Option<String>,
     pub created_at: Option<DateTime<Utc>>,
 }
 
@@ -92,6 +96,7 @@ mod tests {
             content: "  ".to_string(),
             in_reply_to_id: None,
             attachments: vec![],
+            object_id: None,
             created_at: None,
         };
         assert_eq!(post_data_1.validate().is_ok(), false);
@@ -103,6 +108,7 @@ mod tests {
             content: "test ".to_string(),
             in_reply_to_id: None,
             attachments: vec![],
+            object_id: None,
             created_at: None,
         };
         assert_eq!(post_data_2.validate().is_ok(), true);