How to use Regular Expression Tester
- Start by adding the text you want to check into Regular Expression Tester.
- Set Pattern, Flags so the output fits your use case.
- Watch the output update instantly while you adjust the text.
- When it looks right, Copy matches to save it.
About this tool
Regular Expression Tester is a static, client-side tool with no backend. Regular 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. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is Regular Expression Tester for?
Regular Expression Tester lets you check your input right in the browser using the Pattern, Flags controls, with the result shown instantly and nothing uploaded.
Do I need an account for Regular Expression Tester?
No — Regular Expression Tester needs no account, sign-up or installation.
Where is my data processed by Regular Expression Tester?
Entirely in your browser — Regular Expression Tester keeps your data on your own machine and sends nothing anywhere.
Which regex flavor does Regular Expression Tester use?
Regular Expression Tester runs your pattern with the browser's own JavaScript regex engine, live and on your device.
Can I use Regular Expression Tester without a connection?
Yes — after the first load Regular Expression Tester runs entirely offline.