Test regular expressions live
Live match highlighting, flags, groups.
Files stay on your device. No accounts. Free.
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About this tool
Type a pattern, toggle flags (g, i, m, s), and watch matches highlight live in your test string with a running match count and capture-group breakdown. Errors in the pattern are shown as you type instead of silently matching nothing.
The engine is JavaScript's own RegExp, exactly what runs in Node and the browser, so what matches here matches in your code. Your test data stays on your machine.
How it works
- Paste your input, or drop a text file onto the box.
- The output updates live as you type.
- Copy it to the clipboard, or download it as a file.
Frequently asked questions
Which regex flavor does this tester use?
JavaScript's built-in RegExp, the exact engine in Node and every browser. If your target is Python, Java or PCRE, most patterns carry over but lookbehind and some escapes can differ.
What do the g, i, m and s flags do?
g finds all matches instead of stopping at the first, i ignores case, m makes ^ and $ match at line boundaries, and s lets the dot match newline characters.
Why does my pattern match nothing?
If the pattern itself is invalid you get the parser's error message as you type. If it is valid but matchless, check the g flag and remember that special characters like . + ? ( ) need escaping with a backslash to be matched literally.