diff --git a/lib/clacks/inbox.ex b/lib/clacks/inbox.ex
index 30efc77..8218dd9 100644
--- a/lib/clacks/inbox.ex
+++ b/lib/clacks/inbox.ex
@@ -2,6 +2,14 @@ defmodule Clacks.Inbox do
   require Logger
   alias Clacks.{Repo, Activity, Object, Actor, ActivityPub, Notification}
 
+  @spec store_object(map()) :: {:ok, Object.t()}
+  defp store_object(%{"id" => ap_id} = object) do
+    changeset = Object.changeset(Object.get_cached_by_ap_id(ap_id) || %Object{}, %{data: object})
+    {:ok, object} = Repo.insert_or_update(changeset)
+    {:ok, object}
+  end
+
+  @spec store_activity(map(), boolean()) :: {:ok, Activity.t()} | {:error, term()}
   defp store_activity(%{"actor" => actor, "id" => ap_id} = activity, local \\ false)
        when is_binary(actor) do
     # remove the embedded object (if there is one) from the activity
@@ -37,9 +45,8 @@ defmodule Clacks.Inbox do
 
   def handle(%{"type" => "Create", "object" => object} = activity) do
     object = Clacks.Inbox.Transformer.restrict_incoming_object(object)
-    changeset = Object.changeset_for_creating(object)
 
-    with {:ok, _object} <- Repo.insert(changeset),
+    with {:ok, _object} <- store_object(object),
          {:ok, _activity} <- store_activity(activity) do
       :ok
     else
diff --git a/lib/clacks/object.ex b/lib/clacks/object.ex
index 47c26fc..3c0984b 100644
--- a/lib/clacks/object.ex
+++ b/lib/clacks/object.ex
@@ -17,6 +17,7 @@ defmodule Clacks.Object do
     schema
     |> cast(attrs, [:data])
     |> validate_required([:data])
+    |> unique_constraint(:ap_id, name: :objects_unique_ap_id_index)
   end
 
   @spec changeset_for_creating(data :: map()) :: Ecto.Changeset.t()