Validation
Username
Validate usernames that are 3–16 characters long and contain only letters, digits, underscores, and hyphens.
Try it in RegexPro →Available in
Pattern
regexengine-agnostic
^[a-zA-Z0-9_\-]{3,16}$Raw source: ^[a-zA-Z0-9_\-]{3,16}$
How it works
^ and $ anchor to the full string. The character class [a-zA-Z0-9_\-] allows letters (upper and lower), digits, underscores, and hyphens. {3,16} enforces the length range most platforms use for usernames.
Examples
Input
john_doeMatches
john_doe
Input
user-123Matches
user-123
Input
abNo match
—Common use cases
- •User registration form validation
- •API username parameter sanitization
- •Social platform handle creation
- •Database username format enforcement