Playwright Proxy Debugging: Why Your Script Works Locally but Fails With Proxies

A Playwright script can look stable until a proxy enters the workflow. Without a proxy, the page opens. The selector works. The click happens. The test passes. Then you add a proxy. Suddenly the page hangs. Authentication fails. Login behaves differently. A request times out. The same script works in visible mode but fails in headless mode. A retry succeeds once and fails again five minutes later. The first reaction is usually simple: The proxy is bad. Sometimes that is true. But a Playwr...