fastify-swagger VS swagger-jsdoc

With Speakeasy, you can create client SDKs based on an OpenAPI specification. Fastify ships with the @fastify/swagger plugin, which provides convenient shortcuts for generating good OpenAPI specifications. We'll start this tutorial by registering @fastify/swagger in a Fastify project to generate a spec.

First let’s get our current OpenAPI specification out of Fastify and onto the file system. If you have not added the https://github.com/fastify/fastify-swagger plugin first go do that. Then use this simple script I called generate-spec.ts to write your OpenAPI specification to the filesystem.

The fastify-swagger docs has an example https://github.com/fastify/fastify-swagger

@fastify/swagger is a fastify plugin to serve a Swagger UI, using Swagger (OpenAPI v2) or OpenAPI v3 schemas automatically generated from your route schemas, or from an existing Swagger/OpenAPI schema.

On the Node.js framework side of things, Fastify has support for Swagger with the fastify-swagger plugin.

With this approach, backend can be any programming languages that support OpenAPI or Swagger. Personally, I use fastify-swagger; but I can also be things like Python's FastAPI or Golang's Gin/Buffalo/Native.

For this task, we are going to use swagger-jscode. It says that it is to write Swagger, old name of OpenAPI, inside jsdoc, like below

js doc style comments support

There's swagger-ui-express which can work with swagger-jsdoc.

If so, how do you go about generating the interface files? I recently discovered swaggo which generates OpenAPI docs from Go annotations. My Googlefoo then led me to swagger-jsdoc and openapi-comment-parser which do the same thing from JSdoc-like comments. Do you use them, do you use some other module, or do you use some other approach entirely?

Express by itself lacks a lot of metadata useful for generating OpenAPI spec, you'll end up writing a lot of non-standard doc comments. You want to use something like swagger-jsdoc to generate the spec and then some other package to generate the UI.

This article is a continuation of a series about how to build a REST API in Node.js. In the preceding article of this series we added request and response validation that is based on an OpenAPI spec of the API. We used the swagger-jsdoc package to generate this OpenAPI spec from comments in our code that annotate the REST operations.

The swagger-jsdoc package enables us to do this. It looks for JSDoc comments in code (annotated with an @openapi tag) to generate the OpenAPI specification.