Regex Tester
Free online regular-expression tester. Enter a pattern and some text to see the match count and every match in real time, with support for g, i, m and other JavaScript flags. Syntax errors are explained — a fast companion for writing and debugging regex, all locally. DeveloperRuns locally
Use this tool
How to use
- Enter the pattern without the surrounding slashes and set flags (e.g. gi).
- Paste the text to test; results update live.
- The count and the first matches are listed below; a broken pattern shows the reason.
Frequently asked questions
Do I add slashes around the regex?
No — enter only the expression between the slashes and put flags in the separate box, e.g. pattern \d+ with flag g.
Which flags are supported?
Any JavaScript flag is allowed: g (global), i (ignore case), m (multiline), s and u.
Is my text uploaded?
No, matching happens entirely in your browser.