4.0.2 • Public • Published

    Swagger Express Middleware

    Swagger 2.0 middleware and mocks for Express.js

    Cross-Platform Compatibility Build Status

    Coverage Status Tested on APIs.guru Dependencies

    npm License Buy us a tree


    • Supports Swagger 2.0 specs in JSON or YAML
      Swagger Express Middleware uses Swagger-Parser to parse, validate, and dereference Swagger files. You can even split your spec into multiple different files using $ref pointers.

    • Thoroughly tested
      Over 1,000 unit tests and integration tests with 100% code coverage. Tested on over 1,500 real-world APIs from Google, Microsoft, Facebook, Spotify, etc. All tests are run on Mac, Linux, and Windows using all LTS versions of Node.

    • Mock middleware
      Fully-functional mock implementations for every operation in your API, including data persistence, all with zero code! This is a great way to test-drive your API as you write it, or for quick demos and POCs. You can even extend the mock middleware with your own logic and data to fill in any gaps.

    • Metadata middleware
      Annotates each request with all the relevant information from the Swagger definition. The path, the operation, the parameters, the security requirements - they're all easily accessible at req.swagger.

    • Parse Request middleware
      Parses incoming requests and converts everything into the correct data types, according to your Swagger API definition.

    • Validate Request middleware
      Ensures that every request complies with your Swagger API definition, or returns the appropriate HTTP error codes if needed. Of course, you can catch any validation errors and handle them however you want.

    • CORS middleware
      Adds the appropriate CORS headers to each request and automatically responds to CORS preflight requests, all in compliance with your Swagger API definition.

    • Files middleware
      Serves the Swagger API file(s) in JSON or YAML format so they can be used with front-end tools like Swagger UI, Swagger Editor, and Postman.

    Installation and Use

    Install using npm.

    npm install @apidevtools/swagger-express-middleware

    Then use it in your Node.js script like this:

    const express = require('express');
    const createMiddleware = require('@apidevtools/swagger-express-middleware');
    let app = express();
    createMiddleware('PetStore.yaml', app, function(err, middleware) {
        // Add all the Swagger Express Middleware, or just the ones you need.
        // NOTE: Some of these accept optional options (omitted here for brevity)
        app.listen(8000, function() {
            console.log('The PetStore sample is now running at http://localhost:8000');

    Samples & Walkthroughs

    Swagger Express Middleware comes two samples that use the Swagger Pet Store API.

    Sample 1

    This sample demonstrates the most simplistic usage of Swagger Express Middleware. It simply creates a new Express Application and adds all of the Swagger middleware without changing any options, and without adding any custom middleware.

    Sample 2

    This sample demonstrates a few more advanced features of Swagger Express Middleware, such as setting a few options, initializing the mock data store, and adding custom middleware logic.


    I welcome any contributions, enhancements, and bug-fixes. Open an issue on GitHub and submit a pull request.


    To build/test the project locally on your computer:

    1. Clone this repo
      git clone https://github.com/APIDevTools/swagger-express-middleware.git

    2. Install dependencies
      npm install

    3. Run the tests
      npm test

    4. Run the sample app
      npm start


    Swagger Express Middleware is 100% free and open-source, under the MIT license. Use it however you want.

    This package is Treeware. If you use it in production, then we ask that you buy the world a tree to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.

    Big Thanks To

    Thanks to these awesome companies for their support of Open Source developers

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    npm i @apidevtools/swagger-express-middleware

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    Last publish


    • jamesmessinger
    • philsturgeon