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Developer & Web

Regex Tester

Test regular expressions live with highlighted matches, capture groups and a replacement preview.

  • Runs in your browser
  • Works on mobile
  • In: TEXT
  • Out: TEXT
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About Regex Tester

Type a pattern and see every match highlighted as you go, with a table of capture groups and named groups, and an optional preview of what replace() would produce.

The pattern runs in a background worker with a two second limit, so a pattern that backtracks catastrophically - (a+)+$ is the classic - stops the worker instead of freezing the page, and you are told what happened.

This is JavaScript's engine, the same one your browser uses.

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