Regex Tester
Test regular expressions against sample text with live match highlighting, capture groups and replace preview.
Pattern
Find every match, not just the first
Match regardless of upper/lowercase
^ and $ match at each line break
. also matches newline characters
Enables \p{…} property escapes
Test string
Matches highlighted
Add a test string to see matches.
Replace
Use $1, $2 or $<name> to reference capture groups.
Quick reference
| Syntax | Meaning |
|---|---|
. | Any character (except newline unless /s) |
\d \w \s | Digit · word character · whitespace |
\D \W \S | The negation of each |
[abc] [^abc] | One of these · none of these |
* + ? | Zero or more · one or more · optional |
{2} {2,} {2,5} | Exactly · at least · between |
(…) | Capture group |
(?:…) | Group without capturing |
(?<name>…) | Named capture group |
^ $ | Start · end of string (or line with /m) |
\b | Word boundary |
a|b | Either a or b |
(?=…) (?!…) | Lookahead · negative lookahead |
About the regex tester
Write a pattern, toggle the flags and see every match highlighted in your test string as you type. A table below lists each match with its index and named or numbered capture groups broken out. A replace field previews the substituted result, with $1 style references supported, and a quick-reference panel covers the syntax you keep forgetting.
This tool runs entirely in your browser. Nothing you type is uploaded, and it keeps working with no connection at all — including as an installed app.