OpenAPI can be extended by using specification extensions.
While the OpenAPI Specification tries to accommodate most use cases, additional data can be added to extend the specification at certain points.
The extensions properties are implemented as patterned fields that are always prefixed by
Field Pattern Type Description ^x- Any Allows extensions to the OpenAPI Schema. The field name MUST begin with
x-, for example,
x-internal-id. Field names beginning
x-oas-are reserved for uses defined by the OpenAPI Initiative. The value can be
null, a primitive, an array or an object.
The extensions may or may not be supported by the available tooling, but those may be extended as well to add requested support (if tools are internal or open-sourced).
Redocly has created and supports a number of extensions which are represented visually in the API docs.
Redocly also supports additional extensions for lint rules and bundle decorators.