Regex Tester

Test regex with live match highlighting and capture groups.

Pattern

Flags

Test subject

Highlighted matches

Matches2 found

#1 @ 14:hello@sticraft.com

#2 @ 36:support@example.org

How it works

It uses the JavaScript regex engine; other languages (PCRE, Python) have small syntax differences.
Catastrophic-backtracking patterns can be slow. The tester runs them off the main thread but a pathological regex still takes time.

JavaScript's engine. Most syntax is shared across languages, but features like lookbehind or named groups can differ in PCRE or Python.

Yes, matches highlight in the text and each capture group is listed, which is the fastest way to debug a pattern.

No. Matching runs in your browser (off the main thread for responsiveness), so nothing is sent anywhere.