Regex Tester

What is a Regular Expression (Regex)?

A regular expression is a sequence of characters that defines a search pattern. Regex is used for string matching, validation, parsing, and text extraction in virtually all programming languages.

Regex Flags

• g — Global: find all matches
• i — Case-insensitive
• m — Multiline: ^ and $ match line boundaries
• s — Dot-All: . matches newlines

Common Patterns

• Email: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
• URL: https?:\/\/([\w\-]+(\.[\w\-]+)+)(\/\S*)?
• IPv4: (\d{1,3}\.){3}\d{1,3}

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