Test a regular expression against real text
Regular expressions are powerful and unforgiving: one wrong character and a pattern matches nothing, or far too much. This tester lets you build a pattern and see it work against your own text immediately, with every match highlighted and each capture group listed. It runs in your browser, so your pattern and text stay on your device.
How to test
- Enter your pattern and toggle the flags you need: global, ignore case, multiline and dotall.
- Paste your test text and watch matches highlight live as you type.
- Read the groups: capture groups are listed so you can confirm you are pulling out the right parts.
Matches the JavaScript engine exactly
The tester uses your browser's own JavaScript regular-expression engine, so the syntax and behaviour are identical to regex in JavaScript or TypeScript. If a pattern is invalid, you get a clear error instead of a silent failure, which makes it much faster to find the stray bracket or unescaped character. It is ideal for building and debugging a pattern before you drop it into your code.
More developer-friendly tools
When your pattern is ready you might reach for the other Etoolio text tools: convert Markdown to HTML, encode text for a URL, or generate a hash. All of them run locally in your browser, free and unlimited.