What it does
RegExr provides live regular-expression testing for JavaScript and PHP/PCRE, with reference material, test suites and replacement or list output.
Enter sample text and a JavaScript or PHP/PCRE pattern, then inspect matches as you edit. Hover details and the reference help explain captures; Tests can include expected matches and failures. Replace and List produce transformed output. Sign in if you want patterns and favorites retained. Saving creates a shareable public link. Share with the Community goes further: it publishes a copy including the sample text, and the author cannot edit or delete that shared copy.
Strengths
- Live match feedback and reference help
- Tests, replacement and list output
Best for
- Learning a pattern while preparing a text transformation
Sources
- RegExr: Learn, Build, & Test RegEx (Oct 26, 2026)
- RegExr saved links and irreversible Community copies (Oct 26, 2026)
- RegExr source licence (Oct 26, 2026)