diff --git a/scripts/e2e.config.ts b/scripts/e2e.config.ts
index 520fc8338d..a4d74644db 100644
--- a/scripts/e2e.config.ts
+++ b/scripts/e2e.config.ts
@@ -50,7 +50,7 @@ const startApp = resolved.startApp;
  * The one address e2e opens the web app at and the app is told to bind. Never `localhost`: the
  * runner and the app can resolve that name to different addresses.
  */
-const LOOPBACK = "127.0.0.1";
+const LOOPBACK = process.env.T3_PROOF_HOST ?? "127.0.0.1";
 
 /**
  * Leases a device from the Simlock pool, whose gateway speaks agent-device's lease protocol.