How to use Regex Expression Tester
- Paste the pattern and test string you need to check into the input box.
- Set Pattern, Flags so the output fits your use case.
- The result is computed live in your browser as you edit the input.
- When it looks right, Copy matches to save it.
About this tool
Regex Expression Tester runs entirely in your browser. Regex Expression Tester tests your regular expression against sample text in your browser, highlighting matches as you type.
Flags and group captures are surfaced so you can refine the pattern quickly. No data is sent anywhere, so it stays fast and private by default.
Frequently asked questions
What is Regex Expression Tester for?
Regex Expression Tester runs entirely on your device: add your input using the Pattern, Flags controls, and it checks it locally in real time.
Is Regex Expression Tester free to use?
Yes — Regex Expression Tester is completely free, with no usage limits.
Does Regex Expression Tester upload my data?
No — Regex Expression Tester processes everything locally in your browser, so nothing you enter is uploaded or stored.
Which regex flavor does Regex Expression Tester use?
Regex Expression Tester runs your pattern with the browser's own JavaScript regex engine, live and on your device.
Does Regex Expression Tester work on mobile?
Yes — Regex Expression Tester is just a web page and runs on any modern browser, including phones and tablets.