Regex Tester & Builder
Test and build Regular Expressions safely and completely offline.
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Test String
Match Results3 matches
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What is a Regular Expression?
A Regular Expression (often called regex or regexp) is a sequence of characters that specifies a search pattern. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation.
Common Regex Flags
- g (global): Does not return after first match, restarting the subsequent searches from the end of the previous match.
- i (ignore case): Makes the expression case-insensitive.
- m (multiline): Causes
^and$to match the begin/end of each line (not only begin/end of string). - s (dotall): Allows
.to match newline characters.
Privacy First Regex Testing
Many popular online Regex testers require you to paste your sensitive logs, API keys, or customer data into their web forms, which sends that data to their servers for evaluation. This tool evaluates your regex entirely client-side using your browser's built-in JavaScript RegExp engine. Your proprietary test strings never leave your machine.