Write a pattern, paste your text, and watch every match and capture group light up. Invalid syntax is caught and explained before you copy it anywhere.
Regular expressions are the most useful thing most developers forget how to write. You know the shape — "an email-ish thing, then an @, then a domain" — but the actual symbols fight back. This tester is a scratchpad: type the pattern, paste your text, and see immediately what matches and what each capture group caught.
If the pattern is broken, it tells you why instead of failing silently. Great for cleaning data, validating input, or just finally understanding that one regex someone left in the codebase.
Enter a pattern and optional flags, then paste test text. Matches and groups appear live; a bad pattern shows the error so you can fix it.