Regex

Regex tester

Type a pattern and some sample text. Matches are highlighted as you type so you can fix the expression quickly.

Test a pattern

Flags

Use g to find every match, i for case-insensitive search, and m for multiline start and end anchors. Invalid patterns show an error instead of crashing the page.

When to use it

Try a pattern here before you put it in code. It is easier to see a missed capture or an accidental greedy match.

Questions

Which regex flavor is this?

It uses the JavaScript regular expression engine in your browser.

Can I test replace?

This tester highlights matches. It does not run a replace preview.