Test Regular Expressions Live with Highlighted Matches
Regular expressions are powerful but easy to get wrong. The Regex Tester highlights every match as you type and shows capture groups, so you can see exactly what your pattern does before it reaches production.
Open the free Regex Tester →What is the Regex Tester?
Test JavaScript regular expressions live, with highlighted matches and capture groups. It's completely free, needs no sign-up and works on any phone or computer.
Why it's helpful
- Instant visual feedback on every change
- Shows capture groups for extracting data
- Uses the same JavaScript regex engine your browser and Node.js use
Who it's for
Developers, data analysts and anyone cleaning text with patterns.
How to use it
- Type a pattern and flags (g, i, m, s, u).
- Matches highlight as you type; capture groups are listed below.
💻 Open source: this tool is free and open source (MIT License). View the code on GitHub, download it and run it offline.
The bigger picture: Developer
Developers lose a surprising amount of time to small tasks: formatting data, decoding tokens, converting between formats and checking syntax. Fast in-browser tools keep you in flow and keep sensitive data off third-party servers.
What's changing: AI coding assistants now write a lot of code, but developers still need quick, trustworthy tools to inspect and verify what comes out: formatters, validators and decoders matter more, not less.
Frequently asked questions
Which regex flavour?
JavaScript (ECMAScript). Most syntax also works in Python and PHP.
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