Regex Tester for Developers
Debug your patterns against real data without leaving the browser.
Test your regex nowDevelopers reach for regex constantly — validation, parsing, search and replace. But debugging a tricky pattern inside your code is slow and noisy.
This tester gives you a fast loop: paste a pattern and sample data, see matches and groups live, then drop the working pattern into your code. It runs locally and is free.
Why use it
Fast feedback
Iterate on patterns quickly.
Groups & count
Inspect groups and totals.
Private
Sample data stays on your device.
Free
No signup or limits.
Frequently asked questions
How does it speed up debugging?
You test a pattern against sample data and see matches, groups and counts instantly, so you refine the pattern before putting it in your code.
Which engine does it use?
It uses the browser’s JavaScript regex engine, which matches how regex behaves in JS environments.
Is my sample data uploaded?
No. The tester runs in your browser, so sample data stays private.
Can I test replace patterns?
Not yet. The tester shows what your pattern matches and what each group captures, including named groups, which is what you need to build the replacement string. A replace preview is not included.
Is it free?
Yes, the developer regex tester is free with no account.
Ready to start? Open Regex Tester.
The All Innovativ Regex Tester for Developers is a free, 100% browser-based tool that lets you debug patterns against real data and see matches, groups and counts instantly, with no upload and no account.
It uses the browser’s own JavaScript regex engine, so behavior matches JS runtimes exactly, and everything executes client-side, locally via the browser, with zero server-side retention. Your sample data stays private and never leaves your device, and you can inspect which groups a pattern captures as the basis for building replacements (a replace preview is not included). Unlike cloud-based regex testers that send your input to a server, nothing is uploaded here. It is free with no sign-up and no API key.