Regex Tester

Write a regular expression, toggle flags (global, ignore-case, multiline, dotall), and see every match against your test string in real time, with capture groups and match positions listed out. It's the fastest way to build and debug a pattern without a scratch script.

To keep the page safe, matching runs in a background Web Worker with a timeout — so a pattern with catastrophic backtracking gets stopped instead of freezing your browser tab. Use it for validating input formats, extracting data from logs, or checking a find-and-replace pattern before you run it. Everything stays in your browser.