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Regex Tester

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Frequently Asked Questions

What is a regular expression (regex)?

A regular expression is a sequence of characters that defines a search pattern. Regex is used for pattern matching, text search-and-replace, input validation, and data extraction. It is supported natively in virtually every programming language and text editor.

Which regex flavors does this tester support?

The tool supports JavaScript regex (the most common for web developers), and provides guidance for PHP (PCRE) and Python regex syntax. JavaScript regex is the native engine since the tool runs in the browser, but most common patterns work identically across flavors.

Are my regex test patterns and data secure?

Yes. All regex matching runs client-side in your browser. Your test patterns and text data never leave your device. This is important when testing regex against sensitive or proprietary data.