Regex Tester
Write a regular expression and test it against any string. Real-time highlighting, captured groups, and more.
Regular Expression
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Test String
Frequently Asked Questions
What is a regular expression?
A regular expression (regex) is a pattern that describes a set of strings. It's used for searching, matching, and manipulating text. For example, \d+ matches one or more digits.
Is this regex tester free?
Yes, completely free. No signup, no limits. Everything runs in your browser.
Is my data private?
Yes. Your data never leaves your browser. Nothing is sent to any server.
What regex flags are supported?
This tool supports g (global), i (case insensitive), m (multiline), and s (dotAll) flags. You can toggle each flag individually.
What happens if my regex is invalid?
The tool gracefully handles invalid patterns and shows a clear error message so you can fix the syntax.