Regex Tester - Test & Debug Regular Expressions
Test regular expressions against sample text, inspect full matches and capture groups, count results, and use common flags in a fast browser-based debugger.
REGULAR EXPRESSION TESTER
Regular expressions (regex) are powerful tools for pattern matching and text manipulation. Our Regex Tester helps you write, test, and debug your regex patterns in real-time.
Built specifically for JavaScript's regex engine, ensuring what you test here works exactly as it will in your code.
Enter a JavaScript pattern without surrounding slash characters, paste representative sample text, and toggle the global, case-insensitive, or multiline flags. The match list updates as you type and exposes full matches, numbered capture groups, and named groups when the pattern produces them.
Patterns run in the browser's ECMAScript regular-expression engine, not PCRE, Python, .NET, or a server-side flavor, and the interface exposes only the g, i, and m flags. Invalid patterns display an error. Very large samples or expressions with excessive backtracking can still make the browser slow, so test risky patterns on bounded input.
Frequently Asked Questions
- Which regex flavor is supported?
- We support JavaScript Regular Expressions (ECMAScript standards).
- Is my data sent to a server?
- No. All regex processing is done client-side in your browser.
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