Regex Tester Online for JavaScript

Enter a JavaScript regular-expression pattern, choose flags, and test it against realistic sample text. Matches, capture groups, named groups, execution details, and replacement output update in the browser so you can understand what the pattern actually does before adding it to production code.

Include both values that should match and values that must fail. That exposes loose anchors, overly broad character classes, escaping mistakes, and unexpected global or multiline behavior. Patterns run locally in your browser; the text entered into the tester is not submitted to a regex-processing service.

Use the included examples and cheat sheet when debugging email, slug, date, identifier, or extraction patterns. This tool follows JavaScript RegExp behavior, which can differ from PCRE, Python, Java, and .NET engines.