diff --git a/backend/services/proxy.py b/backend/services/proxy.py
index ea8e30a..8cdbcde 100644
--- a/backend/services/proxy.py
+++ b/backend/services/proxy.py
@@ -78,13 +78,21 @@ def username(cfg: dict, session_id: Optional[str] = None) -> str:
 
 
 def playwright_proxy(cfg: dict, session_id: Optional[str] = None) -> Optional[dict]:
-    """Proxy dict for chromium.launch(proxy=...). None when disabled."""
+    """Proxy dict for chromium.launch(proxy=...). None when disabled.
+
+    Credentials are embedded in the server URL rather than passed as separate
+    fields. Separate fields cause Chromium to wait for a 407 challenge before
+    sending auth — DataImpulse takes ~14s to issue that challenge, making every
+    page.goto() timeout. Embedded credentials are sent on the first CONNECT
+    request, bypassing the round-trip entirely.
+    """
     if not is_enabled(cfg):
         return None
+    from urllib.parse import quote
+    user = quote(username(cfg, session_id), safe='')
+    pwd = quote(cfg['password'], safe='')
     return {
-        'server': f"http://{cfg['host']}:{cfg['port']}",
-        'username': username(cfg, session_id),
-        'password': cfg['password'],
+        'server': f"http://{user}:{pwd}@{cfg['host']}:{cfg['port']}",
     }