diff --git a/lib/pleroma/object/fetcher.ex b/lib/pleroma/object/fetcher.ex
index 169298b34..ae4301738 100644
--- a/lib/pleroma/object/fetcher.ex
+++ b/lib/pleroma/object/fetcher.ex
@@ -232,8 +232,24 @@ defp get_object_http(id) do
       |> sign_fetch(id, date)
 
     case HTTP.get(id, headers) do
-      {:ok, %{body: body, status: code}} when code in 200..299 ->
-        {:ok, body}
+      {:ok, %{body: body, status: code, headers: headers}} when code in 200..299 ->
+        case List.keyfind(headers, "content-type", 0) do
+          {_, content_type} ->
+            case Plug.Conn.Utils.media_type(content_type) do
+              {:ok, "application", "activity+json", _} ->
+                {:ok, body}
+
+              {:ok, "application", "ld+json",
+               %{"profile" => "https://www.w3.org/ns/activitystreams"}} ->
+                {:ok, body}
+
+              _ ->
+                {:error, {:content_type, content_type}}
+            end
+
+          _ ->
+            {:error, {:content_type, nil}}
+        end
 
       {:ok, %{status: code}} when code in [404, 410] ->
         {:error, "Object has been deleted"}
diff --git a/test/fixtures/spoofed-object.json b/test/fixtures/spoofed-object.json
new file mode 100644
index 000000000..91e34307d
--- /dev/null
+++ b/test/fixtures/spoofed-object.json
@@ -0,0 +1,26 @@
+{
+  "@context": [
+    "https://www.w3.org/ns/activitystreams",
+    "https://patch.cx/schemas/litepub-0.1.jsonld",
+    {
+      "@language": "und"
+    }
+  ],
+  "actor": "https://patch.cx/users/rin",
+  "attachment": [],
+  "attributedTo": "https://patch.cx/users/rin",
+  "cc": [
+    "https://patch.cx/users/rin/followers"
+  ],
+  "content": "Oracle Corporation (NYSE: ORCL) today announced that it has signed a definitive merger agreement to acquire Pleroma AG (FRA: PLA), for $26.50 per share (approximately $10.3 billion). The transaction has been approved by the boards of directors of both companies and should close by early January.",
+  "context": "https://patch.cx/contexts/spoof",
+  "id": "https://patch.cx/objects/spoof",
+  "published": "2020-10-23T18:02:06.038856Z",
+  "sensitive": false,
+  "summary": "Oracle buys Pleroma",
+  "tag": [],
+  "to": [
+    "https://www.w3.org/ns/activitystreams#Public"
+  ],
+  "type": "Note"
+}
diff --git a/test/pleroma/object/fetcher_test.exs b/test/pleroma/object/fetcher_test.exs
index 14d2c645f..7df6af7fe 100644
--- a/test/pleroma/object/fetcher_test.exs
+++ b/test/pleroma/object/fetcher_test.exs
@@ -21,6 +21,17 @@ defmodule Pleroma.Object.FetcherTest do
       %{method: :get, url: "https://mastodon.example.org/users/userisgone404"} ->
         %Tesla.Env{status: 404}
 
+      %{
+        method: :get,
+        url:
+          "https://patch.cx/media/03ca3c8b4ac3ddd08bf0f84be7885f2f88de0f709112131a22d83650819e36c2.json"
+      } ->
+        %Tesla.Env{
+          status: 200,
+          headers: [{"content-type", "application/json"}],
+          body: File.read!("test/fixtures/spoofed-object.json")
+        }
+
       env ->
         apply(HttpRequestMock, :request, [env])
     end)
@@ -34,19 +45,22 @@ defmodule Pleroma.Object.FetcherTest do
         %{method: :get, url: "https://social.sakamoto.gq/notice/9wTkLEnuq47B25EehM"} ->
           %Tesla.Env{
             status: 200,
-            body: File.read!("test/fixtures/fetch_mocks/9wTkLEnuq47B25EehM.json")
+            body: File.read!("test/fixtures/fetch_mocks/9wTkLEnuq47B25EehM.json"),
+            headers: HttpRequestMock.activitypub_object_headers()
           }
 
         %{method: :get, url: "https://social.sakamoto.gq/users/eal"} ->
           %Tesla.Env{
             status: 200,
-            body: File.read!("test/fixtures/fetch_mocks/eal.json")
+            body: File.read!("test/fixtures/fetch_mocks/eal.json"),
+            headers: HttpRequestMock.activitypub_object_headers()
           }
 
         %{method: :get, url: "https://busshi.moe/users/tuxcrafting/statuses/104410921027210069"} ->
           %Tesla.Env{
             status: 200,
-            body: File.read!("test/fixtures/fetch_mocks/104410921027210069.json")
+            body: File.read!("test/fixtures/fetch_mocks/104410921027210069.json"),
+            headers: HttpRequestMock.activitypub_object_headers()
           }
 
         %{method: :get, url: "https://busshi.moe/users/tuxcrafting"} ->
@@ -132,6 +146,13 @@ test "Return MRF reason when fetched status is rejected by one" do
                  "http://mastodon.example.org/@admin/99541947525187367"
                )
     end
+
+    test "it does not fetch a spoofed object uploaded on an instance as an attachment" do
+      assert {:error, _} =
+               Fetcher.fetch_object_from_id(
+                 "https://patch.cx/media/03ca3c8b4ac3ddd08bf0f84be7885f2f88de0f709112131a22d83650819e36c2.json"
+               )
+    end
   end
 
   describe "implementation quirks" do
diff --git a/test/pleroma/object_test.exs b/test/pleroma/object_test.exs
index 99caba336..5d4e6fb84 100644
--- a/test/pleroma/object_test.exs
+++ b/test/pleroma/object_test.exs
@@ -281,7 +281,11 @@ test "does not fetch unknown objects when fetch_remote is false" do
     setup do
       mock(fn
         %{method: :get, url: "https://patch.cx/objects/9a172665-2bc5-452d-8428-2361d4c33b1d"} ->
-          %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/poll_original.json")}
+          %Tesla.Env{
+            status: 200,
+            body: File.read!("test/fixtures/tesla_mock/poll_original.json"),
+            headers: HttpRequestMock.activitypub_object_headers()
+          }
 
         env ->
           apply(HttpRequestMock, :request, [env])
@@ -315,7 +319,8 @@ test "refetches if the time since the last refetch is greater than the interval"
 
       mock_modified.(%Tesla.Env{
         status: 200,
-        body: File.read!("test/fixtures/tesla_mock/poll_modified.json")
+        body: File.read!("test/fixtures/tesla_mock/poll_modified.json"),
+        headers: HttpRequestMock.activitypub_object_headers()
       })
 
       updated_object = Object.get_by_id_and_maybe_refetch(object.id, interval: -1)
@@ -359,7 +364,8 @@ test "does not refetch if the time since the last refetch is greater than the in
 
       mock_modified.(%Tesla.Env{
         status: 200,
-        body: File.read!("test/fixtures/tesla_mock/poll_modified.json")
+        body: File.read!("test/fixtures/tesla_mock/poll_modified.json"),
+        headers: HttpRequestMock.activitypub_object_headers()
       })
 
       updated_object = Object.get_by_id_and_maybe_refetch(object.id, interval: 100)
@@ -387,7 +393,8 @@ test "preserves internal fields on refetch", %{mock_modified: mock_modified} do
 
       mock_modified.(%Tesla.Env{
         status: 200,
-        body: File.read!("test/fixtures/tesla_mock/poll_modified.json")
+        body: File.read!("test/fixtures/tesla_mock/poll_modified.json"),
+        headers: HttpRequestMock.activitypub_object_headers()
       })
 
       updated_object = Object.get_by_id_and_maybe_refetch(object.id, interval: -1)
diff --git a/test/pleroma/web/activity_pub/activity_pub_test.exs b/test/pleroma/web/activity_pub/activity_pub_test.exs
index 99b1076d6..c6ca37847 100644
--- a/test/pleroma/web/activity_pub/activity_pub_test.exs
+++ b/test/pleroma/web/activity_pub/activity_pub_test.exs
@@ -1410,19 +1410,25 @@ test "doesn't crash when follower and following counters are hidden" do
       mock(fn env ->
         case env.url do
           "http://localhost:4001/users/masto_hidden_counters/following" ->
-            json(%{
-              "@context" => "https://www.w3.org/ns/activitystreams",
-              "id" => "http://localhost:4001/users/masto_hidden_counters/followers"
-            })
+            json(
+              %{
+                "@context" => "https://www.w3.org/ns/activitystreams",
+                "id" => "http://localhost:4001/users/masto_hidden_counters/followers"
+              },
+              headers: HttpRequestMock.activitypub_object_headers()
+            )
 
           "http://localhost:4001/users/masto_hidden_counters/following?page=1" ->
             %Tesla.Env{status: 403, body: ""}
 
           "http://localhost:4001/users/masto_hidden_counters/followers" ->
-            json(%{
-              "@context" => "https://www.w3.org/ns/activitystreams",
-              "id" => "http://localhost:4001/users/masto_hidden_counters/following"
-            })
+            json(
+              %{
+                "@context" => "https://www.w3.org/ns/activitystreams",
+                "id" => "http://localhost:4001/users/masto_hidden_counters/following"
+              },
+              headers: HttpRequestMock.activitypub_object_headers()
+            )
 
           "http://localhost:4001/users/masto_hidden_counters/followers?page=1" ->
             %Tesla.Env{status: 403, body: ""}
@@ -2262,7 +2268,7 @@ test "allow fetching of accounts with an empty string name field" do
     Tesla.Mock.mock(fn
       %{method: :get, url: "https://princess.cat/users/mewmew"} ->
         file = File.read!("test/fixtures/mewmew_no_name.json")
-        %Tesla.Env{status: 200, body: file}
+        %Tesla.Env{status: 200, body: file, headers: HttpRequestMock.activitypub_object_headers()}
     end)
 
     {:ok, user} = ActivityPub.make_user_from_ap_id("https://princess.cat/users/mewmew")
diff --git a/test/pleroma/web/activity_pub/transmogrifier/announce_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/announce_handling_test.exs
index 54335acdb..99c296c74 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/announce_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/announce_handling_test.exs
@@ -60,7 +60,11 @@ test "it works for incoming announces, fetching the announced object" do
 
     Tesla.Mock.mock(fn
       %{method: :get} ->
-        %Tesla.Env{status: 200, body: File.read!("test/fixtures/mastodon-note-object.json")}
+        %Tesla.Env{
+          status: 200,
+          body: File.read!("test/fixtures/mastodon-note-object.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
+        }
     end)
 
     _user = insert(:user, local: false, ap_id: data["actor"])
diff --git a/test/pleroma/web/activity_pub/transmogrifier/article_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/article_handling_test.exs
index 9b12a470a..b0ae804c5 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/article_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/article_handling_test.exs
@@ -13,7 +13,11 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier.ArticleHandlingTest do
 
   test "Pterotype (Wordpress Plugin) Article" do
     Tesla.Mock.mock(fn %{url: "https://wedistribute.org/wp-json/pterotype/v1/actor/-blog"} ->
-      %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/wedistribute-user.json")}
+      %Tesla.Env{
+        status: 200,
+        body: File.read!("test/fixtures/tesla_mock/wedistribute-user.json"),
+        headers: HttpRequestMock.activitypub_object_headers()
+      }
     end)
 
     data =
@@ -36,13 +40,15 @@ test "Plume Article" do
       %{url: "https://baptiste.gelez.xyz/~/PlumeDevelopment/this-month-in-plume-june-2018/"} ->
         %Tesla.Env{
           status: 200,
-          body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-article.json")
+          body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-article.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
         }
 
       %{url: "https://baptiste.gelez.xyz/@/BaptisteGelez"} ->
         %Tesla.Env{
           status: 200,
-          body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-user.json")
+          body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-user.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
         }
     end)
 
@@ -61,7 +67,8 @@ test "Prismo Article" do
     Tesla.Mock.mock(fn %{url: "https://prismo.news/@mxb"} ->
       %Tesla.Env{
         status: 200,
-        body: File.read!("test/fixtures/tesla_mock/https___prismo.news__mxb.json")
+        body: File.read!("test/fixtures/tesla_mock/https___prismo.news__mxb.json"),
+        headers: HttpRequestMock.activitypub_object_headers()
       }
     end)
 
diff --git a/test/pleroma/web/activity_pub/transmogrifier/audio_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/audio_handling_test.exs
index 0636d00c5..181eb7b09 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/audio_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/audio_handling_test.exs
@@ -48,7 +48,8 @@ test "Funkwhale Audio object" do
       %{url: "https://channels.tests.funkwhale.audio/federation/actors/compositions"} ->
         %Tesla.Env{
           status: 200,
-          body: File.read!("test/fixtures/tesla_mock/funkwhale_channel.json")
+          body: File.read!("test/fixtures/tesla_mock/funkwhale_channel.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
         }
     end)
 
diff --git a/test/pleroma/web/activity_pub/transmogrifier/event_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/event_handling_test.exs
index 7f1ef2cbd..d7c55cfbe 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/event_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/event_handling_test.exs
@@ -13,13 +13,15 @@ test "Mobilizon Event object" do
       %{url: "https://mobilizon.org/events/252d5816-00a3-4a89-a66f-15bf65c33e39"} ->
         %Tesla.Env{
           status: 200,
-          body: File.read!("test/fixtures/tesla_mock/mobilizon.org-event.json")
+          body: File.read!("test/fixtures/tesla_mock/mobilizon.org-event.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
         }
 
       %{url: "https://mobilizon.org/@tcit"} ->
         %Tesla.Env{
           status: 200,
-          body: File.read!("test/fixtures/tesla_mock/mobilizon.org-user.json")
+          body: File.read!("test/fixtures/tesla_mock/mobilizon.org-user.json"),
+          headers: HttpRequestMock.activitypub_object_headers()
         }
     end)
 
diff --git a/test/support/http_request_mock.ex b/test/support/http_request_mock.ex
index cb022333f..93464ebff 100644
--- a/test/support/http_request_mock.ex
+++ b/test/support/http_request_mock.ex
@@ -5,6 +5,8 @@
 defmodule HttpRequestMock do
   require Logger
 
+  def activitypub_object_headers, do: [{"content-type", "application/activity+json"}]
+
   def request(
         %Tesla.Env{
           url: url,
@@ -34,7 +36,8 @@ def get("https://osada.macgirvin.com/channel/mike", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https___osada.macgirvin.com_channel_mike.json")
+       body: File.read!("test/fixtures/tesla_mock/https___osada.macgirvin.com_channel_mike.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -42,7 +45,8 @@ def get("https://shitposter.club/users/moonman", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/moonman@shitposter.club.json")
+       body: File.read!("test/fixtures/tesla_mock/moonman@shitposter.club.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -50,7 +54,8 @@ def get("https://mastodon.social/users/emelie/statuses/101849165031453009", _, _
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/status.emelie.json")
+       body: File.read!("test/fixtures/tesla_mock/status.emelie.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -66,7 +71,8 @@ def get("https://mastodon.social/users/emelie", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/emelie.json")
+       body: File.read!("test/fixtures/tesla_mock/emelie.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -78,7 +84,8 @@ def get("https://mastodon.sdf.org/users/rinpatch", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/rinpatch.json")
+       body: File.read!("test/fixtures/tesla_mock/rinpatch.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -86,7 +93,8 @@ def get("https://patch.cx/objects/tesla_mock/poll_attachment", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/poll_attachment.json")
+       body: File.read!("test/fixtures/tesla_mock/poll_attachment.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -99,7 +107,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/webfinger_emelie.json")
+       body: File.read!("test/fixtures/tesla_mock/webfinger_emelie.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -112,7 +121,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/mike@osada.macgirvin.com.json")
+       body: File.read!("test/fixtures/tesla_mock/mike@osada.macgirvin.com.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -190,7 +200,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/lucifermysticus.json")
+       body: File.read!("test/fixtures/tesla_mock/lucifermysticus.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -198,7 +209,8 @@ def get("https://prismo.news/@mxb", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https___prismo.news__mxb.json")
+       body: File.read!("test/fixtures/tesla_mock/https___prismo.news__mxb.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -211,7 +223,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/kaniini@hubzilla.example.org.json")
+       body: File.read!("test/fixtures/tesla_mock/kaniini@hubzilla.example.org.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -219,7 +232,8 @@ def get("https://niu.moe/users/rye", _, _, [{"accept", "application/activity+jso
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/rye.json")
+       body: File.read!("test/fixtures/tesla_mock/rye.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -227,7 +241,8 @@ def get("https://n1u.moe/users/rye", _, _, [{"accept", "application/activity+jso
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/rye.json")
+       body: File.read!("test/fixtures/tesla_mock/rye.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -246,7 +261,8 @@ def get("https://puckipedia.com/", _, _, [{"accept", "application/activity+json"
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/puckipedia.com.json")
+       body: File.read!("test/fixtures/tesla_mock/puckipedia.com.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -254,7 +270,8 @@ def get("https://peertube.moe/accounts/7even", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/7even.json")
+       body: File.read!("test/fixtures/tesla_mock/7even.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -262,7 +279,8 @@ def get("https://peertube.moe/videos/watch/df5f464b-be8d-46fb-ad81-2d4c2d1630e3"
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/peertube.moe-vid.json")
+       body: File.read!("test/fixtures/tesla_mock/peertube.moe-vid.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -270,7 +288,8 @@ def get("https://framatube.org/accounts/framasoft", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https___framatube.org_accounts_framasoft.json")
+       body: File.read!("test/fixtures/tesla_mock/https___framatube.org_accounts_framasoft.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -278,7 +297,8 @@ def get("https://framatube.org/videos/watch/6050732a-8a7a-43d4-a6cd-809525a1d206
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/framatube.org-video.json")
+       body: File.read!("test/fixtures/tesla_mock/framatube.org-video.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -286,7 +306,8 @@ def get("https://peertube.social/accounts/craigmaloney", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/craigmaloney.json")
+       body: File.read!("test/fixtures/tesla_mock/craigmaloney.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -294,7 +315,8 @@ def get("https://peertube.social/videos/watch/278d2b7c-0f38-4aaa-afe6-9ecc0c4a34
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/peertube-social.json")
+       body: File.read!("test/fixtures/tesla_mock/peertube-social.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -304,7 +326,8 @@ def get("https://mobilizon.org/events/252d5816-00a3-4a89-a66f-15bf65c33e39", _,
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/mobilizon.org-event.json")
+       body: File.read!("test/fixtures/tesla_mock/mobilizon.org-event.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -312,7 +335,8 @@ def get("https://mobilizon.org/@tcit", _, _, [{"accept", "application/activity+j
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/mobilizon.org-user.json")
+       body: File.read!("test/fixtures/tesla_mock/mobilizon.org-user.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -320,7 +344,8 @@ def get("https://baptiste.gelez.xyz/@/BaptisteGelez", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-user.json")
+       body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-user.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -328,7 +353,8 @@ def get("https://baptiste.gelez.xyz/~/PlumeDevelopment/this-month-in-plume-june-
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-article.json")
+       body: File.read!("test/fixtures/tesla_mock/baptiste.gelex.xyz-article.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -336,7 +362,8 @@ def get("https://wedistribute.org/wp-json/pterotype/v1/object/85810", _, _, _) d
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/wedistribute-article.json")
+       body: File.read!("test/fixtures/tesla_mock/wedistribute-article.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -344,7 +371,8 @@ def get("https://wedistribute.org/wp-json/pterotype/v1/actor/-blog", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/wedistribute-user.json")
+       body: File.read!("test/fixtures/tesla_mock/wedistribute-user.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -352,7 +380,8 @@ def get("http://mastodon.example.org/users/admin", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/admin@mastdon.example.org.json")
+       body: File.read!("test/fixtures/tesla_mock/admin@mastdon.example.org.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -362,7 +391,8 @@ def get("http://mastodon.example.org/users/relay", _, _, [
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/relay@mastdon.example.org.json")
+       body: File.read!("test/fixtures/tesla_mock/relay@mastdon.example.org.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -482,7 +512,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/pekorino@pawoo.net_host_meta.json")
+       body: File.read!("test/fixtures/tesla_mock/pekorino@pawoo.net_host_meta.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -543,7 +574,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/mastodon-note-object.json")
+       body: File.read!("test/fixtures/mastodon-note-object.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -567,7 +599,8 @@ def get("https://mstdn.io/users/mayuutann", _, _, [{"accept", "application/activ
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/mayumayu.json")
+       body: File.read!("test/fixtures/tesla_mock/mayumayu.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -580,7 +613,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/mayumayupost.json")
+       body: File.read!("test/fixtures/tesla_mock/mayumayupost.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -795,7 +829,8 @@ def get(
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/winterdienst_webfinger.json")
+       body: File.read!("test/fixtures/tesla_mock/winterdienst_webfinger.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -867,12 +902,21 @@ def get("https://social.heldscal.la/.well-known/host-meta", _, _, _) do
   end
 
   def get("https://mastodon.social/users/lambadalambda", _, _, _) do
-    {:ok, %Tesla.Env{status: 200, body: File.read!("test/fixtures/lambadalambda.json")}}
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/lambadalambda.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("https://apfed.club/channel/indio", _, _, _) do
     {:ok,
-     %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/osada-user-indio.json")}}
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/osada-user-indio.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("https://social.heldscal.la/user/23211", _, _, [{"accept", "application/activity+json"}]) do
@@ -895,7 +939,8 @@ def get("http://localhost:4001/users/masto_closed/followers", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/masto_closed_followers.json")
+       body: File.read!("test/fixtures/users_mock/masto_closed_followers.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -903,7 +948,8 @@ def get("http://localhost:4001/users/masto_closed/followers?page=1", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/masto_closed_followers_page.json")
+       body: File.read!("test/fixtures/users_mock/masto_closed_followers_page.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -911,7 +957,8 @@ def get("http://localhost:4001/users/masto_closed/following", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/masto_closed_following.json")
+       body: File.read!("test/fixtures/users_mock/masto_closed_following.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -919,7 +966,8 @@ def get("http://localhost:4001/users/masto_closed/following?page=1", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/masto_closed_following_page.json")
+       body: File.read!("test/fixtures/users_mock/masto_closed_following_page.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -927,7 +975,8 @@ def get("http://localhost:8080/followers/fuser3", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/friendica_followers.json")
+       body: File.read!("test/fixtures/users_mock/friendica_followers.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -935,7 +984,8 @@ def get("http://localhost:8080/following/fuser3", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/friendica_following.json")
+       body: File.read!("test/fixtures/users_mock/friendica_following.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -943,7 +993,8 @@ def get("http://localhost:4001/users/fuser2/followers", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/pleroma_followers.json")
+       body: File.read!("test/fixtures/users_mock/pleroma_followers.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -951,7 +1002,8 @@ def get("http://localhost:4001/users/fuser2/following", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/users_mock/pleroma_following.json")
+       body: File.read!("test/fixtures/users_mock/pleroma_following.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -1049,7 +1101,8 @@ def get("https://info.pleroma.site/activity.json", _, _, [
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity.json")
+       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -1063,7 +1116,8 @@ def get("https://info.pleroma.site/activity2.json", _, _, [
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity2.json")
+       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity2.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -1077,7 +1131,8 @@ def get("https://info.pleroma.site/activity3.json", _, _, [
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity3.json")
+       body: File.read!("test/fixtures/tesla_mock/https__info.pleroma.site_activity3.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -1110,7 +1165,12 @@ def get("https://www.patreon.com/posts/mastodon-2-9-and-28121681", _, _, _) do
   end
 
   def get("http://mastodon.example.org/@admin/99541947525187367", _, _, _) do
-    {:ok, %Tesla.Env{status: 200, body: File.read!("test/fixtures/mastodon-post-activity.json")}}
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/mastodon-post-activity.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("https://info.pleroma.site/activity4.json", _, _, _) do
@@ -1137,7 +1197,8 @@ def get("https://skippers-bin.com/notes/7x9tmrp97i", _, _, _) do
     {:ok,
      %Tesla.Env{
        status: 200,
-       body: File.read!("test/fixtures/tesla_mock/misskey_poll_no_end_date.json")
+       body: File.read!("test/fixtures/tesla_mock/misskey_poll_no_end_date.json"),
+       headers: activitypub_object_headers()
      }}
   end
 
@@ -1146,11 +1207,21 @@ def get("https://example.org/emoji/firedfox.png", _, _, _) do
   end
 
   def get("https://skippers-bin.com/users/7v1w1r8ce6", _, _, _) do
-    {:ok, %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/sjw.json")}}
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/sjw.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("https://patch.cx/users/rin", _, _, _) do
-    {:ok, %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/rin.json")}}
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/rin.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get(
@@ -1160,12 +1231,20 @@ def get(
         _
       ) do
     {:ok,
-     %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/funkwhale_audio.json")}}
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/funkwhale_audio.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("https://channels.tests.funkwhale.audio/federation/actors/compositions", _, _, _) do
     {:ok,
-     %Tesla.Env{status: 200, body: File.read!("test/fixtures/tesla_mock/funkwhale_channel.json")}}
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/funkwhale_channel.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("http://example.com/rel_me/error", _, _, _) do
@@ -1173,7 +1252,12 @@ def get("http://example.com/rel_me/error", _, _, _) do
   end
 
   def get("https://relay.mastodon.host/actor", _, _, _) do
-    {:ok, %Tesla.Env{status: 200, body: File.read!("test/fixtures/relay/relay.json")}}
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/relay/relay.json"),
+       headers: activitypub_object_headers()
+     }}
   end
 
   def get("http://localhost:4001/", _, "", [{"accept", "text/html"}]) do