Developer Browser-based

Regex Tester

Test regular expressions against sample text and view matches.

This tool runs in your browser. Your input is processed locally and is not uploaded.
Matches will appear here.

How to use Regex Tester

Use Regex Tester when you need a quick developer utility without installing software or creating an account. Enter your values or text in the tool above, review the instant result, then copy or save the output when the tool supports it.

  • Works directly in a modern browser on desktop or mobile.
  • Designed for fast repeat use from the root URL /regex-tester.
  • Input stays in your browser unless a tool clearly says otherwise.

Features

  • Pattern and flags input
  • Match list with indexes
  • No server upload
  • Fast browser execution

Use Cases

  • Debug regex patterns
  • Test email or URL matching
  • Learn regular expressions

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Compare two text blocks line by line in your browser.

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Remove extra spaces, empty lines, duplicate lines, and clean up your text.

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Validate JSON and find syntax errors instantly in your browser.

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Frequently Asked Questions

Is this tool free?

Yes. This RunX tool is free to use in your browser.

Does this tool upload my data?

No. The tool runs in your browser and does not send your input to a server.

Can I use it on mobile?

Yes. The interface is responsive and works on modern mobile browsers.