generate fastify routes from a swagger specification
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Fastify swagger generator

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A plugin for fastify to autogenerate a configuration based on a OpenApi(v2/v3) specification.

This project has been replaced by Fastify OpenApi Glue


npm i fastify-swaggergen --save



Add the plugin to your project with register and pass it some basic options and you are done !

const swaggerGen = require("fastify-swaggergen");

const options = {
  swaggerSpec: `${__dirname}/petstore-swagger.v2.json`,
  service: `${__dirname}/service.js`,
  fastifySwagger: {
    disabled: false

fastify.register(swaggerGen, options);

All schema and routes will be taken from the OpenApi specification listed in the options. No need to specify them in your code.


  • swaggerSpec: this can be a JSON object, or the name of a JSON or YAML file containing a valid OpenApi(v2/v3) file
  • service: this can be a javascript object or class, or the name of a javascript file containing such an object. If the import of the file results in a function instead of an object then the function will be executed during import.
  • fastifySwagger: an object containing the options for the fastify-swagger plugin. To avoid registering this plugin pass { fastifySwagger: { disabled: true }}

Of these options swaggerSpec and service are mandatory, fastifySwagger is optional.

See the examples section for a demo.


To make life even more easy there is the swaggergen cli. The swaggergen cli takes a valid OpenApi (v2/v3) file (JSON or YAML) and generates a project including a fastify flugin that you can use on any fastify server, a stub of the service class and a skeleton of a test harness to test the plugin.


  swaggergen [options] <OpenApi specification>

or if you don't have swaggergen installed:

  npx github:seriousme/fastify-swaggergen <OpenApi specification>

This will generate a project based on the provided OpenApi specification. Any existing files in the project folder will be overwritten! See the generator examples section for a demo.


  -p <name>                   The name of the project to generate
  --projectName=<name>        [default: generatedProject]

  -b <dir> --baseDir=<dir>    Directory to generate the project in.
                              This directory must already exist.
                              [default: "."]

The following options are only usefull for testing the swaggergen plugin:
  -c --checksumOnly           Don't generate the project on disk but
                              return checksums only.
  -l --localPlugin            Use a local path to the plugin.

See the generator example section for a demo.


Clone this repository and run npm i


Executing npm start will start fastify on localhost port 3000 with the routes extracted from the petstore example and the accompanying service definition

  "statusCode": 400,
  "error": "Bad Request",
  "message": "params.petId should be integer"
  "statusCode": 500,
  "error": "Internal Server Error",
  "message": "Operation findPetsByStatus not implemented"
  "statusCode": 500,
  "error": "Internal Server Error",
  "message": "name is required!"

as the pet returned by service.js does not match the response schema.


The folder examples/generatedProject contains the result of running swaggergen -l --baseDir=examples examples/petstore/petstore-swagger.v2.yaml. The generated code can be started using npm start in examples/generatedProject (you will need to run npm i in the generated folder first)


Licensed under MIT