toololis
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Password Breach Pattern Check

Heuristic check — common-pattern detector, fully local

🔒 Privacy guarantee: No network request. No analytics on input. Open DevTools → Network tab to verify.
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Learn more — how it works, FAQ & guide
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Password Breach Pattern Check (100% Local)

Heuristic password strength + breach pattern detector. Common passwords, dictionary words, dates, sequences flagged. Zero network — your password never leaves your device.

How to use this tool

  1. 1

    Type password

    NEVER sent — checked locally.

  2. 2

    See pattern flags

    Common patterns flagged.

  3. 3

    Get strength score

    0-100 + crack-time estimate.

Frequently Asked Questions

Is my password sent anywhere?
No — 100% local browser check. No HTTP request, no API call. We only flag pattern + heuristic risk.
Why not check HIBP API?
HIBP's API uses k-anonymity (sends 5-char hash prefix). Privacy-good but still leaks. We chose pure-local — no leak at all. Trade-off: heuristic only.
What does "150 most common" mean?
Top 150 most-leaked passwords from breach corpuses (RockYou, Collection #1). If your password is here, attackers crack it in seconds.

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100% Privacy. This tool runs entirely in your browser. Your data is never uploaded to any server.