Regex Tester
Test regular expressions against input text with real-time match highlighting.
Free Online Regex Tester
Regular expressions are patterns used to match character combinations in strings. They are essential for text processing, form validation, data extraction, search-and-replace operations, and log analysis. This regex tester lets you write a pattern, configure flags (global, case-insensitive, multiline, dotall), and see matches highlighted in real time in your test string. The match details table shows each match's full text, starting index, and length. All processing happens locally using JavaScript's built-in RegExp engine — the same engine used by Node.js and modern browsers. No data is ever sent to a server, making this safe for testing patterns against sensitive data like logs, API responses, or personal information.
Common Regex Patterns
Some frequently used regex patterns include: \d+ (digits), \w+ (word characters), [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} (email), (https?:\/\/)?([\w\-])+\.{1}[a-zA-Z]{2,}([\/\w\-\.\?\,\&\/\\\+&%\$#_]*)? (URL), ^\d{3}-\d{2}-\d{4}$ (SSN format), and (?<=@)\w+ (lookbehind for username extraction). Test any of these patterns with your own text to see exactly what matches and where.