Test regular expressions against text in real-time. Highlights matches, captures groups, shows positions. 100% client-side.
| . | Any character (except newline) |
| \d | Digit [0-9] |
| \D | Not a digit |
| \w | Word character [a-zA-Z0-9_] |
| \W | Not a word character |
| \s | Whitespace (space, tab, newline) |
| \S | Not whitespace |
| [abc] | Any of a, b, or c |
| [^abc] | Not a, b, or c |
| [a-z] | Range: a to z |
| * | 0 or more |
| + | 1 or more |
| ? | 0 or 1 (optional) |
| {n} | Exactly n times |
| {n,} | n or more times |
| {n,m} | Between n and m times |
| *? | 0 or more (lazy) |
| +? | 1 or more (lazy) |
| ^ | Start of string (or line with m) |
| $ | End of string (or line with m) |
| \b | Word boundary |
| \B | Not a word boundary |
| (abc) | Capture group |
| (?:abc) | Non-capturing group |
| (?<name>abc) | Named capture group |
| \1 | Back-reference to group 1 |
| a|b | Alternation (a or b) |
| (?=abc) | Positive lookahead |
| (?!abc) | Negative lookahead |
| (?<=abc) | Positive lookbehind |
| (?<!abc) | Negative lookbehind |
| g | Global — find all matches |
| i | Case-insensitive matching |
| m | Multiline — ^ and $ match line boundaries |
| s | DotAll — . matches newlines too |
| u | Unicode — full Unicode support |
Test your regular expressions instantly with this free online regex tester. Paste your pattern and test string to see real-time match highlighting, captured groups, and match positions. Supports all JavaScript regex flags including global (g), case-insensitive (i), multiline (m), dotAll (s), and unicode (u).
This tool runs entirely in your browser — no data is sent to any server. Your regex patterns and test strings stay private. Use the built-in cheat sheet for quick reference on character classes, quantifiers, anchors, groups, lookahead/lookbehind, and more.
Part of the free developer tools from Clawdia API Catalog — also check out the JSON Formatter, JWT Decoder, and Base64 Encoder.