Regex Tester
Test regular expressions live with highlighted matches and capture groups.
About Regex Tester
Regular expressions are dense, and the fastest way to understand one is to watch it run. This tester compiles your pattern as you type, highlights every match in the sample text and breaks each match into its numbered and named capture groups.
It also includes a replacement preview, so you can confirm that a substitution using $1 style references produces exactly the output you expect before you paste it into your code.
Frequently asked questions
Which regex flavour is this?
JavaScript / ECMAScript regular expressions, exactly as they behave in the browser and in Node.js.
Why does my pattern seem to hang?
Certain nested quantifiers cause catastrophic backtracking. The tester caps the number of matches it collects, but simplifying the pattern is the real fix.
Can I use named capture groups?
Yes. Named groups are supported and are listed by name in the results.