How to use Regex Checker
- Drop your pattern and test string into the field at the top of Regex Checker.
- Set Pattern, Flags so the output fits your use case.
- Regex Checker updates the output automatically as you type.
- When it looks right, Copy pattern to save it.
About this tool
Regex Checker runs entirely in your browser. Regex Checker runs your pattern locally with the JavaScript engine and shows captures live.
Your pattern and test text stay on your device. Your input never leaves the page, and no account or install is required.
Frequently asked questions
What is Regex Checker for?
Use Regex Checker to check your input without installing anything using the Pattern, Flags controls; everything happens client-side.
Is Regex Checker free to use?
Yes — Regex Checker is completely free, with no usage limits.
Where is my data processed by Regex Checker?
Entirely in your browser — Regex Checker keeps your data on your own machine and sends nothing anywhere.
Which regex flavor does Regex Checker use?
Regex Checker runs your pattern with the browser's own JavaScript regex engine, live and on your device.
Does Regex Checker work on mobile?
Yes — Regex Checker is just a web page and runs on any modern browser, including phones and tablets.