/regex

Regex tester

Test JavaScript regex patterns against sample text. Live match highlighting and group capture. Nothing leaves this tab.

Pattern

/ /

Test string

Highlighted

JavaScript regex flavour (ECMAScript). Supports flags: g i m s u y.

What this is: A regular expression is a compact language for describing patterns in text. Useful for validation, extraction, search-and-replace. Notorious for being write-only.
How it works: The pattern and flags are fed to JavaScript's RegExp constructor and matched with matchAll against the test string. Matches are highlighted inline; capture groups appear in the match list. All computation happens in this tab.
Worked example: Pattern: \b(\w+)@(\w+\.\w+)\b Flags: gi Matches: [email protected] → [alex, example.com] [email protected] → [jordan, example.org]
Privacy: Runs entirely in your browser. No network requests. Nothing you paste or type leaves this tab.