Regex Tester
Test JavaScript regular expressions against your own sample text and see matches highlighted as you type. Building a regex by trial and error is far faster when you can watch it match in real time, and this tester shows every match, the full list of captured groups and a running count so you know your pattern does what you intend. You can toggle the common flags for global, case-insensitive, multiline and dotall matching, and invalid patterns produce a clear error instead of silently failing. Enter a pattern and paste text to match against. Everything runs in your browser using the native regex engine, so your patterns and the data you test them on are never uploaded anywhere.
How to use Regex Tester
- Enter your regular expression pattern.
- Toggle any flags you need.
- Paste sample text to test against.
- Read the highlighted matches and groups.
Frequently asked questions
Which regex flavor does it use?
It uses the JavaScript regular expression engine, the same one that runs in the browser, so patterns behave exactly as they would in your JS code.
Can I toggle flags like global or case-insensitive?
Yes. You can turn on flags such as g, i, m and others, and the matches update live to reflect them.
Does it show capture groups?
Yes. It highlights matches in your sample text and shows the captured groups for each match.
What is Regex Tester?
Test JavaScript regular expressions against your own sample text and see matches highlighted as you type. Building a regex by trial and error is far faster when you can watch it match in real time, and this tester shows every match, the full list of captured groups and a running count so you know your pattern does what you intend.
Is Regex Tester free to use?
Yes. Regex Tester is completely free, with no sign-up and no usage limits.
Does Regex Tester work in a web browser?
Yes. Regex Tester runs in any modern web browser. There is nothing to download or install.
Is my data private with Regex Tester?
Yes. Regex Tester runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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Link this tool from a README, doc or site. The badge links back to this page.
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