Regex Tester & Validator

This regex validates dates in DDMMMYY format (day, 3-letter month abbreviation, 2-digit year) with proper month-length validation and leap year checking. It allows days 1-31 for long months (Jan, Mar, May, Jul, Aug, Oct, Dec), 1-30 for short months, 1-28 for February, and 29 for February only in leap years (years divisible by 4). Month abbreviations can be uppercase or mixed case. Useful for validating legacy date formats in military, aviation, or mainframe applications.