A property is nullable if it allows sending
null (in case of JSON/YAML, etc.) or
nil (in case of XML) as value. Several API description formats like Open API, RAML, etc. has support for nullable properties. Transformer now also supports this property and you can convert between different formats without losing this information.
Support for nullable properties is available in several API description formats. The details for this is given below:
- RAML v1.0 supports nullable properties via the nil type.
- API Blueprint supports nullable type attribute in MSON Type specification of Data structures.
- Open API supports nullable schema properties.
- JSON schema used widely in many API description files uses type
nullto indicate nullable properties (http://json-schema.org/latest/json-schema-core.html#rfc.section.4.2.1)
- XML schema used widely in API description formats like WADL and WSDL specifies nullable properties through the nillable attribute.