While the OpenAPI specification tries to accommodate most use cases, additional data can be used to extend the specification and augment its functionality. These additional properties are known as specification extensions (previously called "vendor extensions"). The extension properties are implemented as patterned fields that start with the
x- naming convention.
Redocly has implemented a number of specification extensions to help you enrich your API documentation and adapt your OpenAPI definitions to different scenarios. This page lists specification extensions currently supported by Reference docs and Redoc.
The specification extensions are grouped according to the element(s) of the OpenAPI specification that they extend. Specification extensions can only be used in the sections of your OpenAPI definition that support them - for example, you can't use an extension that modifies the
info object inside the
Select the name of a specification extension in the list to read more on how to use it.
Extend the OpenAPI Root Object.
- x-servers - OpenAPI 2.0 only
- x-webhooks - OpenAPI 2.0 and 3.0 only
Extend the OpenAPI Info Object.
Extend the OpenAPI Tag Object.
Extend the OpenAPI Operation Object.
Extend the OpenAPI Parameter Object.
- x-example and x-examples - OpenAPI 2.0 only
Extend the OpenAPI Response Object.
Extend the OpenAPI Schema Object.
- x-extendedDiscriminator - OpenAPI 2.0 only
- x-nullable - OpenAPI 2.0 only
Extend the OpenAPI Security Scheme Object.
Learn about how to use specification extensions for other purposes such as hiding an API path, operation, or schema property.