I was trying the v3 on a test server and I noticed that if the response to the xhr request to obtain the specification file does not have the proper Content-Type (missing or set to a wrong type) it will fail with No operations defined in spec!.Setting the proper type ( application/json for json or text/plain; charset=utf-8 for yaml) fixes the problem. This means that two GET or two POST methods for the same path . Now you can replace the .openapi() method with your new function. Documenting Your Existing APIs: API Documentation Made Easy with OpenAPI & Swagger, Why You Should Create an API Definition and How To Do It, The Benefits of OpenAPI-Driven API Development, Definition Driven API Development: How OAS & Swagger Help Teams Streamline Their API Development. I can't find how to edit them or where to change this to work let swagger work again. I am trying to setup swagger on top of my node application using the swagger npm package. responses: --- It is up to the specification user to decide whether sub-resources should be referred to as part of their main resource or as a resource of their own. >http://swagger.wordnik.com or on irc.freenode.net, #swagger. Since this is not the place to get such help, and to make sure it's clear, I'll be locking the issue for further comments. The files describing the RESTful API in accordance with the Swagger specification are represented as JSON objects and conform to the JSON standards. layout: "StandaloneLayout", started http-server --cors. issue. The API Declaration - This document describes a resource, including its API calls and models. No operations defined in spec! while loading the JSON file #2757 - Github This is a rather advanced feature. ], Later, when asked to provide documentation for a different project, I went back to Swagger (now OpenAPI) and implemented the specification. But when i want to show it in the UI, I am facing the "No operations defined in spec!" To learn about the latest version, visit OpenAPI 3 pages.