Regex Tester
Write and test regex patterns with instant match highlighting, flag toggles (global, case-insensitive, multiline, dotall), capture group display, and match index tracking. All processing in your browser.
How to Use the Regex Tester
Enter a regular expression pattern in the input field. Type or paste your test string below. Matches are highlighted in real-time as you type. Toggle flags like g (global), i (case-insensitive), m (multiline), and s (dotall) to change matching behavior.
The match details panel shows each match with its index position and any captured groups. If your pattern is invalid, a clear error message is displayed instead.
What Are Regular Expressions?
Regular expressions (regex) are patterns used to match character combinations in strings. They are a powerful tool for searching, replacing, and validating text. Nearly every programming language supports regular expressions.
Common regex elements include: . (any character), * (zero or more), + (one or more), \d (digit), \w (word character), [abc] (character class), and (group) (capture group).
Privacy
All regex matching is performed locally in your browser using the built-in RegExp object. Your test strings are never sent to any server.