Free browser tool · No signup
Regex Tester
Test JavaScript regular expressions, highlight matches and inspect captured groups.
Your input stays in this browser. No API calls or server uploads.
g: all matches · i: ignore case · m: multiline · s: dot matches newlines · u: Unicode · y: sticky
How to use the regex tester
Enter a pattern without surrounding slashes, choose flags, and enter test text. Run the test to view highlighted matches and captured groups. Use g to find multiple matches.
Supported features and limitations
Uses your browser’s JavaScript regex engine. Tests run in a separate worker with a 1.5-second timeout. Supports up to 50,000 text characters, 2,000 pattern characters and 500 displayed matches. Other regex engines may behave differently.
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