Free Regex Tester – Live Regular Expression Matching
Test regular expressions with live match highlighting
Features
- Live highlighted matches
- Capture group inspection
- Flag support (g, i, m, s)
- Clear error messages for invalid patterns
Frequently Asked Questions
This uses JavaScript's native RegExp engine, the same one used in browsers and Node.js.
Yes — capture groups are broken out and shown individually alongside the overall match.
g (global), i (case-insensitive), m (multiline), and s (dotAll) — the standard flags used in JavaScript regex.
A clear error message explains what's wrong, instead of just failing silently.
No — pattern matching runs entirely in your browser.
How to Use Regex Tester
Using Regex Tester is simple and free. No sign-up required.
- Enter your regex pattern and flags.
- Paste test text below.
- Matches highlight automatically as you type.
About Regex Tester
Regex Tester lets you test a regular expression against sample text with live match highlighting, so you can see exactly what your pattern matches — and what it misses — as you refine it, instead of testing blindly in your actual code. It shows capture groups separately, supports all standard flags (g, i, m, s), and gives clear error messages when a pattern is invalid, using JavaScript's native regex engine — the same one used in browsers and Node.js.
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