Regex Tester

Test regular expressions live. Highlights matches and shows capture groups.

100% Private
Your files never leave your device
Lightning fast
Optimised for speed
No sign-up
Use instantly, no account
//gi
Try:
Test string2 matches
Matches & groups
  • 1hello@primova.com
    12–29
    • $1hello
    • $2primova.com
    • userhello
    • domainprimova.com
  • 2admin@example.org
    33–50
    • $1admin
    • $2example.org
    • useradmin
    • domainexample.org

Test and debug regular expressions with live match highlighting, capture-group breakdowns, and a plain-English explanation of your pattern. Includes a replace mode and ready-to-copy code snippets for JavaScript and Python.

How to use Regex Tester

  1. 1Type your pattern and toggle flags (g, i, m, s, u).
  2. 2Paste test text — matches highlight instantly as you type.
  3. 3Inspect each match, its position, and named/numbered groups.
  4. 4Use Replace, read the Explain breakdown, or copy a code snippet.

Frequently asked questions

The JavaScript (ECMAScript) regex engine, including named groups, lookarounds, and Unicode mode. The exported Python snippet maps the common flags for convenience.
Yes. Turn on Explain for a token-by-token, plain-English breakdown — anchors, character classes, quantifiers, groups, and escapes.
Yes. Enable Replace and use $1, $<name>, or $& in the replacement to reference captured groups; the result updates live.
No. Everything runs entirely inside your browser using your own device — your files never leave your computer or get uploaded anywhere. That makes it private and fast, even for large files.
Yes, completely free with no sign-up, no watermark, and no daily limits. Use it as much as you like.

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