Regex Tester
Test a JavaScript regular expression against sample text, toggle flags, and inspect every match without sending your text anywhere.
Debug regular expressions quickly
Regular expressions are famously easy to get almost right and hard to get exactly right. The fastest way to fix one is to see it work: enter your pattern and flags, drop in some sample text, and this tester shows every match, the index where each begins, and a live count — so you can tell at a glance whether the pattern is too greedy, too strict, or missing edge cases.
It uses your browser's native JavaScript RegExp engine, so what you test here behaves exactly like it
will in your code — the same flags (g, i, m, s, u,
y), the same syntax. That makes it reliable for building validation rules, parsing logs, writing
cleanup scripts, and quick text analysis.
Private and instant
Matching happens entirely in your browser as you type, so your patterns and sample text — which often contain real data — never leave the page.
Frequently Asked Questions
What regex flavor does this use?
It uses the JavaScript RegExp engine built into your browser.
Can I test flags?
Yes. Enter flags like g, i, m, s, u, or y in the flags field.
Is the sample text private?
Yes. Matching happens in your browser and the text is not uploaded.
More lightweight utilities for developers, designers, and technical teams.