Regex Tester

About this tool

Test a regular expression against a string and see every match, its position, and any named capture groups.

How to use it

1. Enter your regular expression pattern and any flags (g, i, m, s, u, y).
2. Enter the string to test it against.
3. See whether it matches, plus a full list of matches with their positions and capture groups.

Frequently asked questions

Are there any input limits?

Yes - the pattern is capped at 500 characters and the test string at 100,000 characters, which also caps the worst-case cost of unusually expensive patterns.

What flags are supported?

g, i, m, s, u, and y - the standard JavaScript regular expression flags.