Flags:
About the Regex Tester
Type a regular expression and a test string to see matches highlighted live as you type. Toggle flags like global, ignore-case and multiline, and watch the match count update instantly.
It's the fastest way to build and debug a pattern before using it in code. Everything runs in your browser, so your patterns and text stay private.
Features
- Live match highlighting as you type
- Toggle g, i, m, s and u flags
- Shows the number of matches
- Reports invalid expressions clearly
- Runs entirely in your browser
- Free with no sign-up and privacy-friendly
How to test a regular expression
- Enter your regular expression pattern.
- Choose the flags you need, such as g or i.
- Paste the text you want to test against.
- Review the highlighted matches and the match count.
Frequently asked questions
Which regex syntax is used?
It uses JavaScript's regular-expression engine, the same one that runs in browsers and Node.js.
What do the flags mean?
g matches globally, i ignores case, m is multiline, s lets the dot match newlines, and u enables full Unicode mode.
Are my pattern and text uploaded?
No. Everything is evaluated locally in your browser.
Is it free?
Yes, completely free with no sign-up.