string

A sequence of Unicode characters. No maximum length is prescribed by the vocabulary; systems should define their own limits.

FormatFree text (UTF-8)
JSON typestring

integer

A whole number with no fractional component.

FormatSigned integer (no decimal point)
JSON typenumber (integer)
Examples0, 5, -1

decimal

A numeric value that may include a fractional component. Used for scores, monetary amounts, and measurements.

FormatDecimal number
JSON typenumber
Examples99.50, -12.345, 0.0
NoteFor monetary amounts, pair with a currency property (ISO 4217 code).

boolean

A true/false value.

Formattrue or false
JSON typeboolean

date

A calendar date without a time-of-day component. Follows ISO 8601.

FormatYYYY-MM-DD (ISO 8601 calendar date)
JSON typestring
Examples2024-03-15, 1990-01-01
NoteSystems that only know a birth year may use YYYY or YYYY-01-01 with a precision qualifier. The vocabulary does not prescribe which approach to use.