Username Regex Pattern · Example Matches

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Security · Validation

/^[a-zA-Z0-9_]{3,16}$/

Security · Validation Flags: —

Description

Validates a 3–16 character username made of letters, digits, and underscores. Spaces and special characters are not allowed. Commonly used as the ID rule on sign-up forms.

Example Matches

cool_user_99

regexFan

Test String

cool_user_99

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