Regex Tester

Test regular expressions with live highlighting, capture groups, pattern explanation, and quick-reference. Export in JS, Python, or Go.

How It Works

1

Write your pattern

Enter a regular expression and toggle flags (global, case-insensitive, multiline, etc.).

2

Test against sample text

Paste your test string and see all matches highlighted in real-time.

3

Inspect and export

View capture groups, read the pattern explanation, and copy in JS, Python, or Go format.

FAQ

The tool uses your browser's native JavaScript RegExp engine, which supports ES2018+ features including named groups and lookbehind.
Catastrophic backtracking can occur with nested quantifiers like (a+)+. The tool shows execution time to help identify slow patterns.
Yes. Enable the 'm' flag to make ^ and $ match line boundaries, and the 's' flag to make . match newlines.

Built & Maintained by Varstatt

Varstatt is a one-person product studio run by Jurij Tokarski, product engineer since 2011. These tools are free and open — no signup, no catch.