[5] In March 2015, SmartBear Software acquired the open-source Swagger API specification from Reverb Technologies, Wordnik's parent company.

[6] In November 2015, SmartBear announced that it was donating the Swagger specification to a new organization called the OpenAPI Initiative, under the sponsorship of the Linux Foundation.

Other founding member companies included 3scale, Apigee, Capital One, Google, IBM, Intuit, Microsoft, PayPal, and Restlet.

[11] Major changes in OpenAPI Specification 3.1.0 include JSON schema vocabularies alignment, new top-level elements for describing webhooks that are registered and managed out of band, support for identifying API licenses using the standard SPDX identifier, allowance of descriptions alongside the use of schema references and a change to make the PathItems object optional to simplify creation of reusable libraries of components.

The event has its origins in the API Strategy and Practice Conference (APIStrat) that ran for many years and became part of the OpenAPI Initiative in 2016.