The OpenAPI Specification (originally known as the Swagger Specification) is a specification for machine-readable interface files for describing, producing, consuming, and visualizing RESTful Web services. A variety of tools can generate code, documentation and test cases given an interface file. Development of the OpenAPI Specification (OAS) is overseen by the Open API Initiative, an open source collaborative project of the Linux Foundation.
Both the specification and a framework implementation started as initiatives from Wordnik. Swagger was developed for Wordnik's own use during the development of Wordnik Developer and the underlying API. Swagger development began in early 2010. In March 2015 SmartBear Software acquired the open-source Swagger API specification from Reverb technologies.
In November 2015 SmartBear, the company that maintained the Swagger spec and associated tools, announced that it was helping create a new organization, under the sponsorship of the Linux Foundation, called the Open API Initiative. A variety of companies, including Google, IBM and Microsoft are founding members. SmartBear donated the Swagger specification to the new group. RAML and API Blueprint were also under consideration by the group.
On 1 January 2016 the Swagger specification was renamed the OpenAPI Specification, and was moved to a new repository in GitHub.
SmartBear continues to develop tooling under the Swagger brand to support the OpenAPI specification. In 2016 SmartBear received the API Award in the API Infrastructure category for Swagger.
In 2017, OpenAPI released a preview of version 3.0 of its spec. MuleSoft, the main contributor to the alternative RESTful API Modeling Language (RAML), joined the OAS and open sourced their API Modeling Framework tool, which can generate OAS documents from RAML input.
Applications implemented based on OpenAPI interface files can automatically generate documentation of methods, parameters and models. This helps keep the documentation, client libraries, and source code in sync.
The OpenAPI Specification is language-agnostic. It is also extensible into new technologies and protocols beyond HTTP.
With OpenAPI's declarative resource specification, clients can understand and consume services without knowledge of server implementation or access to the server code.
Tools that work with OpenAPI
The Swagger UI framework allows both developers and non-developers to interact with the API in a sandbox UI that gives insight into how the API responds to parameters and options. Swagger may utilize both JSON and XML.
Swagger-Codegen contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing the OpenAPI definition.
- Representational State Transfer
- Overview of RESTful API Description Languages including RAML, WADL, WSDL, and others
- "Linux Foundation wants to extend Swagger in connected buildings | Business Cloud News". Retrieved 2016-04-22.
- "swagger-api/swagger-spec". GitHub. Retrieved 2015-12-01.
- "SmartBear Assumes Sponsorship of Swagger API Open Source Project". SmartBear. Retrieved 2015-03-25.
- "SmartBear, Linux Foundation launch Open API Initiative to Evolve Swagger". ProgrammableWeb. 2015-11-10. Retrieved 2016-04-21.
- "New Collaborative Project to Extend Swagger Specification for Building Connected Applications and Services". www.linuxfoundation.org. Retrieved 2016-04-22.
- Montcheuil, Yves de. "In 2016, the need for an API meta-language will crystallize". InfoWorld. Retrieved 2016-04-25.
- "Amazon API Gateway Now Supports Swagger Definition Import". InfoQ. Retrieved 2016-04-25.
- API World 2016
- "The OpenAPI Spec, Based on Swagger, Reaches 3.0". InfoQ. Retrieved 2017-05-14.
- "The HTTP API Space is Consolidating around OAS". InfoQ. Retrieved 2017-05-14.