Regex Tester
Test regular expressions against sample text with live match highlighting.
Highlighted matches
0 matches
Key features
Type a regular expression and some test text, and every match is highlighted live, with a list of matches and their capture groups below — supports the standard g, i, m, and s flags.
Matching runs entirely in your browser using JavaScript’s native regex engine. Nothing you enter is sent anywhere.
How to use
Enter a pattern
Type your regular expression, and toggle flags as needed.
Paste your test text
Matches are highlighted directly in the text as you type.
Check the matches list
See every match and its capture groups below.
Frequently asked questions
Which regex engine does this use?
It uses your browser’s built-in JavaScript regex engine (via the RegExp object), so behavior matches exactly what you’d get writing regex in JavaScript — which is very close to, but not always identical to, regex in other languages like Python or PCRE.
What do the flags mean?
"g" (global) finds all matches instead of stopping at the first one. "i" makes matching case-insensitive. "m" (multiline) makes ^ and $ match the start/end of each line rather than the whole string. "s" (dot-all) makes . match newline characters too.
Is my pattern or test text sent anywhere?
No. Matching happens entirely in your browser — nothing is transmitted or stored.