Test and debug regular expressions with live matching and explanations
Test regular expressions instantly - validate and debug regex patterns
A Regex Tester is an essential tool for developers to test and debug regular expressions. Whether you're validating input, parsing text, or searching patterns, our regex tester provides instant testing with match highlighting and detailed explanations.
Regular expressions (regex) are patterns used to match character combinations in strings. They're powerful tools for text processing, validation, and search operations in programming.
Example: /\d{3}-\d{3}-\d{4}/ matches phone numbers like 123-456-7890
g (global): Find all matches, not just first. i (case-insensitive): Ignore case. m (multiline): ^ and $ match line starts/ends.
Use backslash (\) before special characters: . * + ? ^ $ { } [ ] ( ) | \. Example: \. matches a literal period.
Parentheses () create capture groups that extract matched portions. Example: /(\d{3})-(\d{3})/ captures area code and prefix separately.
Most regex syntax is standard, but some features vary between languages (JavaScript, Python, Java). Our tester uses JavaScript regex syntax.
Email: /^[\w.-]+@[\w.-]+\.\w+$/
Phone: /\d{3}-\d{3}-\d{4}/
URL: /https?:\/\/[\w.-]+/
Digits: /\d+/
Letters: /[a-zA-Z]+/
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