KaiZen OpenAPI Editor is an Eclipse-based editor for the OpenAPI Specification (OAS). OpenAPI v2, formerly known as the Swagger specification, is the most widely used and supported API description language, and OpenAPI v3 is a new major version, released in July 2017 with significant new features and improvements.
KaiZen OpenAPI Editor supports both OpenAPI v2 and v3, and it's available now on the Eclipse Marketplace.