Regex Tester — Build & Debug Regular Expressions Free

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Test and debug regular expressions with live highlighting

Build and test regular expressions in real time. See matches highlighted instantly, inspect capture groups, and debug your patterns — all in your browser, nothing uploaded.

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Highlighted matches (7)

Hello World, this is a Sample Text with Some Capitalized Words.

Match details

Helloat index 0
Worldat index 6
Sampleat index 23
Textat index 30
Someat index 40
Capitalizedat index 45
Wordsat index 57

Common flags: g global, i case-insensitive, m multiline, s dotAll. All processing happens instantly in your browser — nothing is sent to a server.

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📖 Learn More

Regex Tester Guide: Learn and Debug Regular Expressions Fast

Regular expressions are powerful but unforgiving — one wrong character and nothing matches. Here's how to test and debug them visually, for free.

7 min read
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