Regex Tester
Test a JavaScript regular expression against sample text.
How to test a regular expression
Type your regex pattern and some sample text, and the tester highlights every match in real time as you edit. Toggle flags like global, case-insensitive and multiline to see exactly how your pattern behaves. It's an essential tool for building and debugging patterns for search, validation and data extraction.
Why use a live regex tester?
Regular expressions are powerful but easy to get subtly wrong — a live tester lets you iterate quickly and catch mistakes before you drop a pattern into code. Seeing matches highlighted instantly removes the guesswork. The matching runs in your browser, so your patterns and test data stay private on your device.
Related Tools
Frequently Asked Questions
Which regex engine does it use?
It uses JavaScript regular expressions, the same syntax used in browsers and Node.js.
Can I set regex flags?
Yes. Enter flags like g, i, m, or u in the flags field to control global, case-insensitive, multiline, and Unicode matching.
How do I see what my regex matches?
Enter a pattern and test string and the matches are shown instantly, so you can refine the expression as you type.
Is the regex tester free and private?
Yes. It is free, needs no sign-up, and runs in your browser, so your patterns and text are never uploaded.