Alpha validates if a string contains English letters only (a-zA-Z).

Alphanumeric validates if a string contains English letters and digits only (a-zA-Z0-9).

ASCII validates if a string contains ASCII characters only.

Base64 validates if a string is encoded in Base64.

CountryCode2 validates if a string is a valid ISO3166 Alpha 2 country code.

CountryCode3 validates if a string is a valid ISO3166 Alpha 3 country code.

CreditCard validates if a string is a valid credit card number.

CurrencyCode validates if a string is a valid IsISO4217 currency code.

DataURI validates if a string is a valid base64-encoded data URI.

DialString validates if a string is a valid dial string that can be passed to Dial().

Digit validates if a string contains digits only (0-9).

DNSName validates if a string is valid DNS name.

Domain validates if a string is valid domain.

E164 validates if a string is a valid ISO3166 Alpha 2 country code.

Email validates if a string is an email or not.

Float validates if a string is a floating point number.

FullWidth validates if a string contains full-width characters.

HalfWidth validates if a string contains half-width characters.

Hexadecimal validates if a string is a valid hexadecimal number.

HexColor validates if a string is a valid hexadecimal color code.

Host validates if a string is a valid IP (both v4 and v6) or a valid DNS name.

Int validates if a string is a valid integer number.

IP validates if a string is a valid IP address (either version 4 or 6).

IPv4 validates if a string is a valid version 4 IP address.

IPv6 validates if a string is a valid version 6 IP address.

ISBN validates if a string is an ISBN (either version 10 or 13).

ISBN10 validates if a string is an ISBN version 10.

ISBN13 validates if a string is an ISBN version 13.

JSON validates if a string is in valid JSON format.

Latitude validates if a string is a valid latitude.

Longitude validates if a string is a valid longitude.

LowerCase validates if a string contains lower case unicode letters only.

MAC validates if a string is a MAC address.

MongoID validates if a string is a valid Mongo ID.

Multibyte validates if a string contains multibyte characters.

Port validates if a string is a valid port number.

PrintableASCII validates if a string contains printable ASCII characters only.

RequestURI validates if a string is a valid request URI.

RequestURL validates if a string is a valid request URL.

RGBColor validates if a string is a valid RGB color in the form of rgb(R, G, B).

Semver validates if a string is a valid semantic version.

SSN validates if a string is a social security number (SSN).

Subdomain validates if a string is valid subdomain.

UpperCase validates if a string contains upper case unicode letters only.

URL validates if a string is a valid URL.

UTFDigit validates if a string contains unicode decimal digits only.

UTFLetter validates if a string contains unicode letters only.

UTFLetterNumeric validates if a string contains unicode letters and numbers only.

UTFNumeric validates if a string contains unicode number characters (category N) only.

UUID validates if a string is a valid UUID.

UUIDv3 validates if a string is a valid version 3 UUID.

UUIDv4 validates if a string is a valid version 4 UUID.

UUIDv5 validates if a string is a valid version 5 UUID.

VariableWidth validates if a string contains both full-width and half-width characters.