diff --git a/tools/mock/mock_peertube.py b/tools/mock/mock_peertube.py
index 142c7a1..6f2235e 100644
--- a/tools/mock/mock_peertube.py
+++ b/tools/mock/mock_peertube.py
@@ -34,8 +34,22 @@ import urllib.request
 from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 
 UPSTREAM = "https://peertube2.cpy.re"
+UP_HOST = "peertube2.cpy.re"
 AVATAR = UPSTREAM + "/lazy-static/avatars/73e78544-cbae-439e-8c84-98b0756fbde7.jpg"
 PORT = int(sys.argv[1]) if len(sys.argv) > 1 else 8080
+# How the emulator addresses this proxy. The app decides a video/channel is
+# "local" by matching its host against the instance host, so we relabel the
+# upstream host to ours in the JSON (only the `host` fields, never URLs, so
+# thumbnails/media keep pointing at peertube2).
+MOCK_HOST = f"10.0.2.2:{PORT}"
+
+
+def relabel_hosts(obj):
+    if isinstance(obj, dict):
+        return {k: (MOCK_HOST if k == "host" and v == UP_HOST else relabel_hosts(v)) for k, v in obj.items()}
+    if isinstance(obj, list):
+        return [relabel_hosts(x) for x in obj]
+    return obj
 
 
 def fetch(path_with_query):
@@ -54,7 +68,7 @@ class Handler(BaseHTTPRequestHandler):
         pass
 
     def _json(self, obj, code=200):
-        data = json.dumps(obj).encode()
+        data = json.dumps(relabel_hosts(obj)).encode()
         self.send_response(code)
         self.send_header("Content-Type", "application/json")
         self.send_header("Content-Length", str(len(data)))
@@ -127,9 +141,16 @@ class Handler(BaseHTTPRequestHandler):
             return self._json(detail)
 
         # Everything else (video lists, detail, channels, thumbnails) is proxied.
+        # A handle the app built with our host (name@10.0.2.2:PORT) is mapped back
+        # to the upstream host before we ask peertube2.
+        upstream = self.path.replace(MOCK_HOST, UP_HOST).replace(
+            MOCK_HOST.replace(":", "%3A"), UP_HOST)
         try:
-            code, ctype, body = fetch(self.path)
-            self._raw(code, ctype, body)
+            code, ctype, body = fetch(upstream)
+            if "json" in ctype:
+                self._json(json.loads(body), code)  # relabel hosts in proxied JSON too
+            else:
+                self._raw(code, ctype, body)
         except urllib.error.HTTPError as e:
             self._raw(e.code, "application/json", e.read())
         except Exception as e:  # noqa: BLE001