A Visual Guide to What's New in Swagger 3.0

Swagger 2 has transitioned to become OpenAPI Specification under the Linux Foundation, and the new OpenAPI 3.0 version introduces several updates and improvements over its predecessor. These changes include adopting Semver for versioning, replacing Github Flavored Markdown with CommonMark, and expanding support for JSON Schema features. OpenAPI 3.0 allows more flexibility in defining URLs, introduces path templating, and enhances the clarity of JSON References. Furthermore, it refines the structure of components, such as headers and requestBodies, which can now incorporate examples and support different media types. The response format benefits from wildcard response codes and the introduction of callbacks for webhooks. A significant addition is the linking feature, which provides a way to navigate between API resources, similar to hypermedia APIs. Security has also been updated, with new names and support for multiple OAuth2 flows and OpenID Connect. Although upgrading from Swagger 2.0 to OpenAPI 3.0 is lossless, the OpenAPI 3.0 specifications are not backward compatible with tools that only support Swagger 2. The final specification is yet to be released, but OpenAPI 3.0 is considered feature complete, offering solutions to many limitations encountered with Swagger 2.