Regex Tester
Test regular expressions with real-time highlighting and match groups. 100% client-side processing.
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What is a Regular Expression?
A regular expression (regex or regexp) is a sequence of characters that defines a search pattern. It is used for pattern matching within strings, enabling powerful text search, validation, and manipulation. Regex is supported in virtually every programming language including JavaScript, Python, Java, Go, and many more.
Common Use Cases
Developers use regex for validating user input (emails, phone numbers, URLs), searching and replacing text in code editors, parsing log files, extracting data from structured text, and building lexers or tokenizers for compilers and interpreters.