PAC File Tester
Paste a PAC file. Trace exactly which rule matches a test URL — and why the ones above it didn't. Lint for the classic mistakes. Everything runs in your browser: no uploads, no accounts, zero network requests. Open devtools and watch.
Your PAC file is parsed as data, never executed as code, and never leaves this page. The simulator can't do real DNS — that's the point — so fill in "resolves to" if your file relies on it. Both browser modes are always checked; you'll be warned when a URL routes differently between modern browsers and legacy full-URL stacks. I audited this tool and wrote up everything I found — including the bug that froze it for 35 seconds.
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