Darmowy Regex Tester & Debugger Online
Test regular expressions with real-time highlighting and capture groups.
Highlighted Matches
Match Details
0 matchesQuick Reference
.Any character except newline
\dDigit (0-9)
\wWord character (a-z, A-Z, 0-9, _)
\sWhitespace (space, tab, newline)
^Start of string (or line with m flag)
$End of string (or line with m flag)
*0 or more of previous
+1 or more of previous
?0 or 1 of previous
{n,m}Between n and m of previous
[abc]Character class: a, b, or c
[^abc]Not a, b, or c
(abc)Capture group
(?:abc)Non-capturing group
a|ba or b
\bWord boundary
(?=abc)Positive lookahead
(?!abc)Negative lookahead
About Regular Expressions
Regular expressions (regex) are patterns used to match character combinations in strings. They are an essential tool in programming, text processing, data validation, and search operations. Every major programming language supports regex · JavaScript, Python, Java, PHP, Ruby, Go, and more.
This tester uses JavaScript's built-in RegExp engine, which supports ECMAScript regex syntax including lookaheads, character classes, quantifiers, and the g, i, m, and s flags. Matches are highlighted in real time as you type, and capture groups are displayed in the match details panel.
Common Uses
- Validate email addresses, phone numbers, and form inputs
- Extract data from log files, CSVs, or HTML
- Find and replace text patterns in code editors
- Parse URLs, file paths, and structured text
- Write web scraping selectors and search filters
Frequently Asked Questions
What do the g, i, m, and s flags do?
g (global) finds all matches instead of stopping at the first. i (case insensitive) ignores uppercase vs. lowercase. m (multiline) makes ^ and $ match the start/end of each line. s (dotAll) makes . match newline characters too.
Will this regex work in Python / Java / PHP?
Most regex syntax is shared across languages. However, there are differences · for example, JavaScript doesn't support lookbehinds in all browsers (though modern ones do), and Python uses different named group syntax. For basic patterns, what works here will work everywhere.
Is my test data sent anywhere?
No. All regex matching happens locally in your browser using JavaScript's native RegExp engine. Nothing is sent to any server.