How to Use Regex Tester
Build and debug regular expressions with instant feedback. Matches are highlighted in your test string and broken out into a table with their index and capture groups. Toggle flags (g, i, m, s, u, y) with a click.
Open the Regex Tester tool →What is Regex Tester?
Test JavaScript regular expressions against sample text with live highlighting and capture groups. It's completely free, needs no sign-up, and runs entirely in your browser — so it's fast and private.
How to use Regex Tester
- Open the Regex Tester tool.
- Paste or type your input.
- Set any options provided.
- Copy the result. Everything runs in your browser — nothing is uploaded.
Frequently asked questions
Which regex flavour does it use?
JavaScript's regular-expression engine, so patterns behave exactly as they will in the browser and Node.js.
Can I see capture groups?
Yes — matches are highlighted live and numbered or named capture groups are listed so you can debug the pattern.
Which flags are supported?
The standard JavaScript flags, including g (global), i (case-insensitive), m (multiline) and s (dotall).
Ready to try it?
Open Regex Tester →