Developer
Regex Tester
Test patterns, flags, capture groups, and matches. Everything happens on this device.
Tip: press Ctrl/⌘ + Enter
Your input stays private
This tool runs entirely in your browser. DevCalc does not send or store the content you enter.
How to use Regex Tester
- Enter a regular-expression pattern and flags.
- Paste the text to search.
- Review match positions and captured groups.
Example and important notes
The pattern “(Dev\w+)” finds words beginning with Dev and reports the first capture group.
- Regex syntax and supported features vary by programming language.
- Avoid patterns with catastrophic backtracking on untrusted long input.
Frequently asked questions
What does the g flag do?
It finds all matches instead of stopping after the first.
Why does a pattern work here but not elsewhere?
This tester uses the JavaScript regular-expression engine.