Developer & Security
Write a regex pattern and instantly see which parts of the text match, which groups are captured, and the result of a replacement. Common example patterns for email addresses, phone numbers and URLs are included.
Free · no sign-up · runs in your browser · updated
Type a regex pattern and choose the flags you need (g, i, m, s, u, y).
Paste your test text. Matches are highlighted and the list of capture groups is shown.
Fill in the replacement box to see the replaced result, then copy the pattern into your code.
\d matches one digit, \w one letter, digit or underscore, and \s one whitespace character. The + sign means one or more, * zero or more, ? optional, and {n,m} a specific count. Parentheses ( ) create a capture group, [abc] is a character set, and ^ and $ mark the start and end. Example: \d{4}-\d{2}-\d{2} matches a date such as 2026-10-26.
This tool uses your browser’s built-in regex engine (ECMAScript), so results match what runs in JavaScript and Node.js. Other languages such as PHP, Python or Java differ slightly in syntax, for example for lookbehind and named groups. Very complex patterns can run slowly (catastrophic backtracking); this tool runs them in a separate worker and stops them after about two seconds.
g: find all matches, not just the first. i: ignore case. m: ^ and $ apply per line. s: the dot also matches line breaks. u: full Unicode support. y: match only from a specific position (sticky).
In the replacement box, $1, $2 and so on refer to the first, second and later groups. $& is the whole match. Named groups are referenced with $<name>.
Patterns with nested repetition such as (a+)+ can hit exponential backtracking on certain text. Simplify the pattern or avoid nested quantifiers.
Most basic patterns work, but advanced features such as lookbehind or named groups differ between languages. Test again in your target language.
No. Testing runs in your browser.
Need more than tools?
These tools are only a small part of what Tipamedia can build. Tell us what you need and we will help you work out the next step.