JSON Schema String Formats

A calendar date in ISO 8601 format: YYYY-MM-DD. Use this when the time of day is not relevant.

A time of day in HH:MM:SS format with a required timezone. Use Z for UTC or an offset like +05:30. The timezone cannot be omitted.

A precise moment in time following ISO 8601: date and time joined by the letter T, with a required timezone.

A time interval in ISO 8601 duration format. Starts with P, followed by date components (Y=years, M=months, D=days) and time components after T (H=hours, M=minutes, S=seconds). For example, P1Y6M means 1 year and 6 months.

A standard internet email address. Must contain exactly one @ symbol, with a name before it and a domain after.

An email address that can include non-Latin characters. Use this instead of email when your users may have addresses in their native script.

A network hostname — the domain name of a server or website. Each label may contain ASCII letters, digits, and hyphens, but cannot start or end with a hyphen.

A network hostname that can include non-ASCII characters, per the Internationalized Domain Names standard. Use this when the domain uses local-script characters.

A Uniform Resource Identifier — a complete address that includes a scheme such as https://, ftp://, or mailto:.

A URI that can be either absolute (with a scheme) or relative (just a path). Use this when a link may reference a resource on the same server without repeating the full domain.

A web address pattern with named placeholders in curly braces that get filled in later.

A complete web address that can contain non-Latin characters. The international version of uri.

A complete or relative web address that can contain non-Latin characters. The international version of uri-reference.

An IPv4 address — four decimal numbers from 0 to 255, separated by dots, used to identify a device on a network.

An IPv6 address — eight groups of four hexadecimal digits separated by colons. Consecutive all-zero groups can be shortened to ::.

A Universally Unique Identifier — a 128-bit value formatted as 32 hexadecimal digits in five hyphen-separated groups. Generated independently, UUIDs are statistically guaranteed not to collide.

An address that pinpoints a specific value inside a JSON document, like a file path. Each / goes one level deeper: /users/0/name means “the name field of the first item in users”. Must start with /.

Like json-pointer, but starting from your current position in the document rather than the top. A number at the start says how many levels to go up first.

A regular expression pattern. This format validates that the pattern syntax is correct, not that a given string matches it. To restrict field values to a specific pattern, use the Pattern constraint.