API specifications overview

This page applies to Apigee and Apigee hybrid.

API specifications use standard formats to describe APIs. They are machine readable, but also easy for humans to read and understand. Specifications typically describe elements of an API such as its base path, paths and verbs, headers, query parameters, operations, content types, response descriptions.

An API version can contain multiple API specifications of the same or different type. API hub supports several specification formats, including:

  • OpenAPI specifications for REST APIs
  • Protocol Buffers for RPC APIs
  • Web Service Definition Language (WSDL) for SOAP APIs
  • MCP schema files for Model Context Protocol (MCP) APIs

Using API specifications with API hub

You can create an API version in API hub with or without an API specification. You can upload a specification at the time you create a version, or you can attach one to an existing version. When you view the details of an API in the user interface, you will see a list of any specs that are associated with the versions of that API resource

For more information, see Manage API specifications.

Specification parsing

Where supported, API hub can parse an API specification to extract information about the API and store it with an API version. This parsing process is what populates the version with its specific operations or tools.

API hub supports specification parsing for the following formats:

  • OpenAPI specifications: For versions with the REST API style, API hub parses the OpenAPI file to extract the API's operations.
  • MCP schema: For versions with the MCP API style, API hub parses the MCP schema file to extract the API's tools.

API hub also supports specification validation. For more information, see Validate an API specification.

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