howsafeismyapp

Free tool

Source Map Checker

Bundlers can ship .map files that reconstruct your original source — comments, internal URLs, sometimes secrets. If they're publicly reachable, so is your app's blueprint. This checks in seconds.

passive · no signup · nothing stored

What this checks

How the check works

We load your production page, find the bundles it references and check whether their .map files are publicly reachable. If they are, anyone can rebuild your original source. Passive, read-only, nothing stored.

Common questions

Why are exposed source maps a problem?

A source map hands an attacker your app's original code — structure, comments, internal endpoints and occasionally hardcoded keys. Combined with a leaked secret it turns a finding into an incident (Art. 32 GDPR).

Aren't source maps useful?

Yes — for debugging and your error-tracking vendor. The fix isn't to stop generating them, but to stop serving them publicly.

How do I fix it?

Disable source-map upload in your production build (one flag in most bundlers) or restrict the .map files to your error-tracking vendor rather than shipping them to every visitor.

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