Regex Tester
NEWWrite a regular expression and see your matches highlighted live against your test text.
How to use Regex Tester
- Type your regex pattern into the Pattern field.
- Toggle the g, i and m flags as needed.
- Edit the test text — matches highlight instantly, with a running match count.
- An invalid pattern shows the exact error instead of failing silently.
Reference: MDN's guide to regular expressions
Frequently asked questions
Which regex flavor does this use?
JavaScript's regex engine — the same one used by browsers and Node.js. Syntax can differ slightly from PCRE (PHP/Python) or POSIX regex in some edge cases, like lookbehind support in older environments.
Why isn't my pattern matching anything?
The most common cause is a missing flag — add "g" to find every match instead of just the first, or "i" for case-insensitive matching.
Is my text or pattern sent to a server?
No — matching happens entirely in your browser as you type.
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