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Regex Tester
Tests regular expressions live against sample text, highlighting every match and capture group with an explanation.
Developer
Nothing uploaded
No sign-up
Free, unlimited
Paste something on the left to see the result.
In short
Regex Tester is a free online tool on inputtesthub.com that tests regular expressions live against sample text, highlighting every match and capture group with an explanation. It needs no account, no download and no payment, and there is no daily usage limit. Everything is processed inside your own browser, so the data you paste is never uploaded to a server.
How to use the Regex Tester
- Paste your code into the input area.
- Choose the indentation and output options you want.
- Read the formatted result, then copy or download it.
About the Regex Tester
The Regex Tester tests regular expressions live against sample text, highlighting every match and capture group with an explanation. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Building a pattern before putting it in code.
- Understanding a regex someone else wrote.
- Testing a validation rule against real edge cases.
Details
| Engine | The JavaScript RegExp engine, so results match exactly what runs in a browser or Node |
|---|---|
| Shown | Every match with its index, all capture groups, named groups, and total match count |
| Flags | g, i, m, s, u and y are all supported |
Frequently asked questions
Is the Regex Tester free?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is the Regex Tester safe to use with private information?
No. The Regex Tester runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
When would I actually need the Regex Tester?
The jobs it is built for: building a pattern before putting it in code. Understanding a regex someone else wrote. Testing a validation rule against real edge cases. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
What are the reference figures here?
Engine is The JavaScript RegExp engine, so results match exactly what runs in a browser or Node. Shown is Every match with its index, all capture groups, named groups, and total match count. Flags is g, i, m, s, u and y are all supported. These are printed on the page itself, so you do not have to take them on trust.
Can I use the Regex Tester on mobile?
Yes. The page is responsive and the page works in Chrome, Safari, Firefox, Edge and Samsung Internet on both Android and iOS. There is no app to install and nothing to sign into.
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