diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bd41752cd..b848d3c98 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,7 @@
 image: git.pleroma.social:5050/pleroma/pleroma/ci-base
 
 variables: &global_variables
+  # Only used for the release
   ELIXIR_VER: 1.12.3
   POSTGRES_DB: pleroma_test
   POSTGRES_USER: postgres
@@ -319,8 +320,9 @@ amd64:
           - deps
   variables: &release-variables
     MIX_ENV: prod
+    VIX_COMPILATION_MODE: PLATFORM_PROVIDED_LIBVIPS
   before_script: &before-release
-  - apt-get update && apt-get install -y cmake libmagic-dev
+  - apt-get update && apt-get install -y cmake libmagic-dev libvips-dev erlang-dev
   - echo "import Config" > config/prod.secret.exs
   - mix local.hex --force
   - mix local.rebar --force
@@ -341,7 +343,7 @@ amd64-musl:
   cache: *release-cache
   variables: *release-variables
   before_script: &before-release-musl
-  - apk add git build-base cmake file-dev openssl
+  - apk add git build-base cmake file-dev openssl vips-dev
   - echo "import Config" > config/prod.secret.exs
   - mix local.hex --force
   - mix local.rebar --force
diff --git a/changelog.d/authorize-interaction.add b/changelog.d/authorize-interaction.add
new file mode 100644
index 000000000..8692209e1
--- /dev/null
+++ b/changelog.d/authorize-interaction.add
@@ -0,0 +1 @@
+Support /authorize-interaction route used by Mastodon
\ No newline at end of file
diff --git a/changelog.d/build-release-with-local-libvips.skip b/changelog.d/build-release-with-local-libvips.skip
new file mode 100644
index 000000000..e69de29bb
diff --git a/changelog.d/optimistic-inbox.change b/changelog.d/optimistic-inbox.change
new file mode 100644
index 000000000..2cf1ce92c
--- /dev/null
+++ b/changelog.d/optimistic-inbox.change
@@ -0,0 +1 @@
+Optimistic Inbox reduces the processing overhead of incoming activities without instantly verifiable signatures.
diff --git a/lib/pleroma/user.ex b/lib/pleroma/user.ex
index ce125d608..0706f5607 100644
--- a/lib/pleroma/user.ex
+++ b/lib/pleroma/user.ex
@@ -2136,7 +2136,7 @@ def public_key(%{public_key: public_key_pem}) when is_binary(public_key_pem) do
   def public_key(_), do: {:error, "key not found"}
 
   def get_public_key_for_ap_id(ap_id) do
-    with {:ok, %User{} = user} <- get_or_fetch_by_ap_id(ap_id),
+    with %User{} = user <- get_cached_by_ap_id(ap_id),
          {:ok, public_key} <- public_key(user) do
       {:ok, public_key}
     else
diff --git a/lib/pleroma/web/activity_pub/activity_pub_controller.ex b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
index 1357c379c..3b2193ca3 100644
--- a/lib/pleroma/web/activity_pub/activity_pub_controller.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
@@ -287,10 +287,9 @@ def inbox(%{assigns: %{valid_signature: true}} = conn, params) do
     json(conn, "ok")
   end
 
-  def inbox(%{assigns: %{valid_signature: false}} = conn, _params) do
-    conn
-    |> put_status(:bad_request)
-    |> json("Invalid HTTP Signature")
+  def inbox(%{assigns: %{valid_signature: false}, req_headers: req_headers} = conn, params) do
+    Federator.incoming_ap_doc(%{req_headers: req_headers, params: params})
+    json(conn, "ok")
   end
 
   # POST /relay/inbox -or- POST /internal/fetch/inbox
diff --git a/lib/pleroma/web/federator.ex b/lib/pleroma/web/federator.ex
index 84b77cda1..8621d984c 100644
--- a/lib/pleroma/web/federator.ex
+++ b/lib/pleroma/web/federator.ex
@@ -35,6 +35,17 @@ def allowed_thread_distance?(distance) do
   end
 
   # Client API
+  def incoming_ap_doc(%{params: params, req_headers: req_headers}) do
+    ReceiverWorker.enqueue(
+      "incoming_ap_doc",
+      %{"req_headers" => req_headers, "params" => params, "timeout" => :timer.seconds(20)},
+      priority: 2
+    )
+  end
+
+  def incoming_ap_doc(%{"type" => "Delete"} = params) do
+    ReceiverWorker.enqueue("incoming_ap_doc", %{"params" => params}, priority: 3)
+  end
 
   def incoming_ap_doc(params) do
     ReceiverWorker.enqueue("incoming_ap_doc", %{"params" => params})
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index eb8576b02..38391cc8f 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -471,6 +471,8 @@ defmodule Pleroma.Web.Router do
     get("/main/ostatus", UtilController, :show_subscribe_form)
     get("/ostatus_subscribe", RemoteFollowController, :follow)
     post("/ostatus_subscribe", RemoteFollowController, :do_follow)
+
+    get("/authorize_interaction", RemoteFollowController, :authorize_interaction)
   end
 
   scope "/api/pleroma", Pleroma.Web.TwitterAPI do
diff --git a/lib/pleroma/web/twitter_api/controllers/remote_follow_controller.ex b/lib/pleroma/web/twitter_api/controllers/remote_follow_controller.ex
index 6229d5d05..178ad2b43 100644
--- a/lib/pleroma/web/twitter_api/controllers/remote_follow_controller.ex
+++ b/lib/pleroma/web/twitter_api/controllers/remote_follow_controller.ex
@@ -121,6 +121,13 @@ def do_follow(%{assigns: %{user: nil}} = conn, _) do
     render(conn, "followed.html", %{error: "Insufficient permissions: follow | write:follows."})
   end
 
+  # GET /authorize_interaction
+  #
+  def authorize_interaction(conn, %{"uri" => uri}) do
+    conn
+    |> redirect(to: Routes.remote_follow_path(conn, :follow, %{acct: uri}))
+  end
+
   defp handle_follow_error(conn, {:mfa_token, followee, _} = _) do
     render(conn, "follow_login.html", %{error: "Wrong username or password", followee: followee})
   end
diff --git a/lib/pleroma/workers/receiver_worker.ex b/lib/pleroma/workers/receiver_worker.ex
index cf1bb62b4..1dddd8d2e 100644
--- a/lib/pleroma/workers/receiver_worker.ex
+++ b/lib/pleroma/workers/receiver_worker.ex
@@ -3,24 +3,56 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Workers.ReceiverWorker do
+  alias Pleroma.Signature
+  alias Pleroma.User
   alias Pleroma.Web.Federator
 
   use Pleroma.Workers.WorkerHelper, queue: "federator_incoming"
 
   @impl Oban.Worker
+
+  def perform(%Job{
+        args: %{"op" => "incoming_ap_doc", "req_headers" => req_headers, "params" => params}
+      }) do
+    # Oban's serialization converts our tuple headers to lists.
+    # Revert it for the signature validation.
+    req_headers = Enum.into(req_headers, [], &List.to_tuple(&1))
+
+    conn_data = %{params: params, req_headers: req_headers}
+
+    with {:ok, %User{} = _actor} <- User.get_or_fetch_by_ap_id(conn_data.params["actor"]),
+         {:ok, _public_key} <- Signature.refetch_public_key(conn_data),
+         {:signature, true} <- {:signature, HTTPSignatures.validate_conn(conn_data)},
+         {:ok, res} <- Federator.perform(:incoming_ap_doc, params) do
+      {:ok, res}
+    else
+      e -> process_errors(e)
+    end
+  end
+
   def perform(%Job{args: %{"op" => "incoming_ap_doc", "params" => params}}) do
     with {:ok, res} <- Federator.perform(:incoming_ap_doc, params) do
       {:ok, res}
     else
+      e -> process_errors(e)
+    end
+  end
+
+  @impl Oban.Worker
+  def timeout(%_{args: %{"timeout" => timeout}}), do: timeout
+
+  def timeout(_job), do: :timer.seconds(5)
+
+  defp process_errors(errors) do
+    case errors do
       {:error, :origin_containment_failed} -> {:cancel, :origin_containment_failed}
       {:error, :already_present} -> {:cancel, :already_present}
       {:error, {:validate_object, reason}} -> {:cancel, reason}
       {:error, {:error, {:validate, reason}}} -> {:cancel, reason}
       {:error, {:reject, reason}} -> {:cancel, reason}
+      {:signature, false} -> {:cancel, :invalid_signature}
+      {:error, {:error, reason = "Object has been deleted"}} -> {:cancel, reason}
       e -> e
     end
   end
-
-  @impl Oban.Worker
-  def timeout(_job), do: :timer.seconds(5)
 end
diff --git a/mix.exs b/mix.exs
index 99074b433..653e5694b 100644
--- a/mix.exs
+++ b/mix.exs
@@ -181,7 +181,7 @@ defp deps do
       {:majic, "~> 1.0"},
       {:open_api_spex, "~> 3.16"},
       {:ecto_psql_extras, "~> 0.6"},
-      {:vix, "~> 0.25.0"},
+      {:vix, "~> 0.26.0"},
       {:elixir_make, "~> 0.7.7", override: true},
       {:blurhash, "~> 0.1.0", hex: :rinpatch_blurhash},
 
diff --git a/mix.lock b/mix.lock
index a5afb46d5..81a05687b 100644
--- a/mix.lock
+++ b/mix.lock
@@ -137,7 +137,7 @@
   "ueberauth": {:hex, :ueberauth, "0.10.5", "806adb703df87e55b5615cf365e809f84c20c68aa8c08ff8a416a5a6644c4b02", [:mix], [{:plug, "~> 1.5", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "3efd1f31d490a125c7ed453b926f7c31d78b97b8a854c755f5c40064bf3ac9e1"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
   "unsafe": {:hex, :unsafe, "1.0.1", "a27e1874f72ee49312e0a9ec2e0b27924214a05e3ddac90e91727bc76f8613d8", [:mix], [], "hexpm", "6c7729a2d214806450d29766abc2afaa7a2cbecf415be64f36a6691afebb50e5"},
-  "vix": {:hex, :vix, "0.25.0", "b294ca3140c0357b262d86e9966949949844282b81923bb990668c1ee5a35337", [:make, :mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:cc_precompiler, "~> 0.1.4 or ~> 0.2", [hex: :cc_precompiler, repo: "hexpm", optional: false]}, {:elixir_make, "~> 0.7.3 or ~> 0.8", [hex: :elixir_make, repo: "hexpm", optional: false]}, {:kino, "~> 0.7", [hex: :kino, repo: "hexpm", optional: true]}], "hexpm", "be09c96982978bc2d0c501a73e0b65ba58ec94c1afb94e3617029d6ce7ae8c3f"},
+  "vix": {:hex, :vix, "0.26.0", "027f10b6969b759318be84bd0bd8c88af877445e4e41cf96a0460392cea5399c", [:make, :mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:cc_precompiler, "~> 0.1.4 or ~> 0.2", [hex: :cc_precompiler, repo: "hexpm", optional: false]}, {:elixir_make, "~> 0.7.3 or ~> 0.8", [hex: :elixir_make, repo: "hexpm", optional: false]}, {:kino, "~> 0.7", [hex: :kino, repo: "hexpm", optional: true]}], "hexpm", "71b0a79ae7f199cacfc8e679b0e4ba25ee47dc02e182c5b9097efb29fbe14efd"},
   "web_push_encryption": {:hex, :web_push_encryption, "0.3.1", "76d0e7375142dfee67391e7690e89f92578889cbcf2879377900b5620ee4708d", [:mix], [{:httpoison, "~> 1.0", [hex: :httpoison, repo: "hexpm", optional: false]}, {:jose, "~> 1.11.1", [hex: :jose, repo: "hexpm", optional: false]}], "hexpm", "4f82b2e57622fb9337559058e8797cb0df7e7c9790793bdc4e40bc895f70e2a2"},
   "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
   "websock_adapter": {:hex, :websock_adapter, "0.5.5", "9dfeee8269b27e958a65b3e235b7e447769f66b5b5925385f5a569269164a210", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "4b977ba4a01918acbf77045ff88de7f6972c2a009213c515a445c48f224ffce9"},
diff --git a/test/pleroma/signature_test.exs b/test/pleroma/signature_test.exs
index b849cbee7..f5a915fa8 100644
--- a/test/pleroma/signature_test.exs
+++ b/test/pleroma/signature_test.exs
@@ -43,10 +43,7 @@ test "it returns key" do
     end
 
     test "it returns error when not found user" do
-      assert capture_log(fn ->
-               assert Signature.fetch_public_key(make_fake_conn("https://test-ap-id")) ==
-                        {:error, :error}
-             end) =~ "[error] Could not decode user"
+      assert Signature.fetch_public_key(make_fake_conn("https://test-ap-id")) == {:error, :error}
     end
 
     test "it returns error if public key is nil" do
diff --git a/test/pleroma/user_test.exs b/test/pleroma/user_test.exs
index b9df527a0..77ca9198b 100644
--- a/test/pleroma/user_test.exs
+++ b/test/pleroma/user_test.exs
@@ -1951,8 +1951,8 @@ test "unsuggests a user" do
     end
   end
 
-  test "get_public_key_for_ap_id fetches a user that's not in the db" do
-    assert {:ok, _key} = User.get_public_key_for_ap_id("http://mastodon.example.org/users/admin")
+  test "get_public_key_for_ap_id returns correctly for user that's not in the db" do
+    assert :error = User.get_public_key_for_ap_id("http://mastodon.example.org/users/admin")
   end
 
   describe "per-user rich-text filtering" do
diff --git a/test/pleroma/web/plugs/frontend_static_plug_test.exs b/test/pleroma/web/plugs/frontend_static_plug_test.exs
index 6d6ac0f8e..6f4d24d9e 100644
--- a/test/pleroma/web/plugs/frontend_static_plug_test.exs
+++ b/test/pleroma/web/plugs/frontend_static_plug_test.exs
@@ -89,6 +89,7 @@ test "api routes are detected correctly" do
       "api",
       "main",
       "ostatus_subscribe",
+      "authorize_interaction",
       "oauth",
       "objects",
       "activities",
diff --git a/test/pleroma/web/twitter_api/remote_follow_controller_test.exs b/test/pleroma/web/twitter_api/remote_follow_controller_test.exs
index b0812667e..41f8ebcd7 100644
--- a/test/pleroma/web/twitter_api/remote_follow_controller_test.exs
+++ b/test/pleroma/web/twitter_api/remote_follow_controller_test.exs
@@ -460,4 +460,38 @@ test "local avatar is not proxied" do
       assert avatar_url == "#{Pleroma.Web.Endpoint.url()}/localuser/avatar.png"
     end
   end
+
+  describe "GET /authorize_interaction - authorize_interaction/2" do
+    test "redirects to /ostatus_subscribe", %{conn: conn} do
+      Tesla.Mock.mock(fn
+        %{method: :get, url: "https://mastodon.social/users/emelie"} ->
+          %Tesla.Env{
+            status: 200,
+            headers: [{"content-type", "application/activity+json"}],
+            body: File.read!("test/fixtures/tesla_mock/emelie.json")
+          }
+
+        %{method: :get, url: "https://mastodon.social/users/emelie/collections/featured"} ->
+          %Tesla.Env{
+            status: 200,
+            headers: [{"content-type", "application/activity+json"}],
+            body:
+              File.read!("test/fixtures/users_mock/masto_featured.json")
+              |> String.replace("{{domain}}", "mastodon.social")
+              |> String.replace("{{nickname}}", "emelie")
+          }
+      end)
+
+      conn =
+        conn
+        |> get(
+          remote_follow_path(conn, :authorize_interaction, %{
+            uri: "https://mastodon.social/users/emelie"
+          })
+        )
+
+      assert redirected_to(conn) ==
+               remote_follow_path(conn, :follow, %{acct: "https://mastodon.social/users/emelie"})
+    end
+  end
 end