diff --git a/src/activity_pub/activity.rs b/src/activity_pub/activity.rs
index f3f77d90..ce2e91e3 100644
--- a/src/activity_pub/activity.rs
+++ b/src/activity_pub/activity.rs
@@ -9,6 +9,8 @@ use activity_pub::object::Object;
 pub trait Activity {
     fn get_id(&self) -> String;
 
+    fn get_type(&self) -> String;    
+
     fn serialize(&self) -> serde_json::Value;
 
     // fn deserialize(serde_json::Value) -> Self;
@@ -25,7 +27,7 @@ pub struct Accept {
 impl Accept {
     pub fn new<A: Activity, B: Actor>(who: &B, what: &A, conn: &PgConnection) -> Accept {
         Accept {
-            id: "TODO".to_string(),
+            id: format!("{}/accept/{}/{}", who.compute_id(conn), what.get_type().to_lowercase(), what.get_id()),
             actor: serde_json::Value::String(who.compute_id(conn)),
             object: serde_json::Value::String(what.get_id()),
             date: chrono::Utc::now()
@@ -38,6 +40,10 @@ impl Activity for Accept {
         self.id.clone()
     }
 
+    fn get_type(&self) -> String {
+        "Accept".to_string()
+    }
+
     fn serialize(&self) -> serde_json::Value {
         json!({
             "type": "Accept",
@@ -59,7 +65,7 @@ pub struct Create {
 impl Create {
     pub fn new<A: Actor, B: Object>(actor: &A, obj: &B, conn: &PgConnection) -> Create {
         Create {
-            id: "TODO".to_string(),
+            id: format!("{}/activity", obj.compute_id(conn)),
             actor: serde_json::Value::String(actor.compute_id(conn)),
             object: obj.serialize(conn),
             date: chrono::Utc::now()
@@ -72,6 +78,10 @@ impl Activity for Create {
         self.id.clone()
     }
 
+    fn get_type(&self) -> String {
+        "Create".to_string()
+    }
+
     fn serialize(&self) -> serde_json::Value {
         json!({
             "type": "Create",
@@ -93,7 +103,7 @@ pub struct Follow {
 impl Follow {
     pub fn new<A: Actor, B: Actor>(follower: &A, following: &B, conn: &PgConnection) -> Follow {
         Follow {
-            id: "TODO".to_string(),
+            id: format!("{}/follow/{}", follower.compute_id(conn), following.compute_id(conn)),
             actor: serde_json::Value::String(follower.compute_id(conn)),
             object: serde_json::Value::String(following.compute_id(conn)),
             date: chrono::Utc::now()
@@ -119,6 +129,10 @@ impl Activity for Follow {
         self.id.clone()
     }
 
+    fn get_type(&self) -> String {
+        "Follow".to_string()
+    }
+
     fn serialize(&self) -> serde_json::Value {
         json!({
             "type": "Follow",
diff --git a/src/activity_pub/object.rs b/src/activity_pub/object.rs
index ff5338b8..c705d236 100644
--- a/src/activity_pub/object.rs
+++ b/src/activity_pub/object.rs
@@ -5,6 +5,8 @@ use activity_pub::actor::Actor;
 
 pub trait Object {
     fn serialize(&self, conn: &PgConnection) -> serde_json::Value;
+
+    fn compute_id(&self, conn: &PgConnection) -> String;
 }
 
 pub trait Attribuable {
diff --git a/src/models/posts.rs b/src/models/posts.rs
index 1dfc0eb8..2da6d002 100644
--- a/src/models/posts.rs
+++ b/src/models/posts.rs
@@ -3,9 +3,11 @@ use diesel::{self, PgConnection, RunQueryDsl, QueryDsl, ExpressionMethods, Belon
 use diesel::dsl::any;
 use serde_json;
 
-use activity_pub::PUBLIC_VISIBILTY;
+use BASE_URL;
+use activity_pub::{PUBLIC_VISIBILTY, ap_url};
 use activity_pub::actor::Actor;
 use activity_pub::object::Object;
+use models::blogs::Blog;
 use models::users::User;
 use models::post_authors::PostAuthor;
 use schema::posts;
@@ -63,9 +65,22 @@ impl Post {
         let author_list = PostAuthor::belonging_to(self).select(post_authors::author_id);
         users::table.filter(users::id.eq(any(author_list))).load::<User>(conn).unwrap()
     }
+
+    pub fn get_blog(&self, conn: &PgConnection) -> Blog {
+        use schema::blogs;
+        blogs::table.filter(blogs::id.eq(self.blog_id))
+            .limit(1)
+            .load::<Blog>(conn)
+            .expect("Couldn't load blog associted to post")
+            .into_iter().nth(0).unwrap()
+    }
 }
 
 impl Object for Post {
+    fn compute_id(&self, conn: &PgConnection) -> String {
+        ap_url(format!("{}/{}/{}", BASE_URL.as_str(), self.get_blog(conn).actor_id, self.slug))
+    }
+
     fn serialize(&self, conn: &PgConnection) -> serde_json::Value {
         json!({
             "type": "Article",