JSON Server

Get a full fake REST API with zero coding in less than 30 seconds (seriously)

Created with <3 for front-end developers who need a quick back-end for prototyping and mocking.

• Egghead.io free video tutorial - Creating demo APIs with json-server
• JSONPlaceholder - Live running version

See also:

• 🏨 hotel - Get local domains in seconds
• 🐶 husky - Git hooks made easy

Example

Create a db.json file

{
  "posts": [
    { "id": 1, "title": "json-server", "author": "typicode" }
  ],
  "comments": [
    { "id": 1, "body": "some comment", "postId": 1 }
  ],
  "profile": { "name": "typicode" }
}

Start JSON Server

$ json-server --watch db.json

Now if you go to http://localhost:3000/posts/1, you'll get

{ "id": 1, "title": "json-server", "author": "typicode" }

Also when doing requests, its good to know that

• If you make POST, PUT, PATCH or DELETE requests, changes will be automatically and safely saved to db.json using lowdb.
• Your request body JSON should be object enclosed, just like the GET output. (for example {"name": "Foobar"})
• Id values are not mutable. Any id value in the body of your PUT or PATCH request wil be ignored. Only a value set in a POST request wil be respected, but only if not already taken.
• A POST, PUT or PATCH request should include a Content-Type: application/json header to use the JSON in the request body. Otherwise it will result in a 200 OK but without changes being made to the data.

Install

$ npm install -g json-server

Routes

Based on the previous db.json file, here are all the default routes. You can also add other routes using --routes.

Plural routes

GET    /posts
GET    /posts/1
POST   /posts
PUT    /posts/1
PATCH  /posts/1
DELETE /posts/1

Singular routes

GET    /profile
POST   /profile
PUT    /profile
PATCH  /profile

Filter

Use . to access deep properties

GET /posts?title=json-server&author=typicode
GET /posts?id=1&id=2
GET /comments?author.name=typicode

Paginate

Add _page and in the Link header you'll get first, prev, next and last links

GET /posts?_page=7

10 items are returned by default

Sort

Add _sort and _order (ascending order by default)

GET /posts?_sort=views&_order=DESC
GET /posts/1/comments?_sort=votes&_order=ASC

Slice

Add _start and _end or _limit (an X-Total-Count header is included in the response)

GET /posts?_start=20&_end=30
GET /posts/1/comments?_start=20&_end=30
GET /posts/1/comments?_start=20&_limit=10

Operators

Add _gte or _lte for getting a range

GET /posts?views_gte=10&views_lte=20

Add _ne to exclude a value

GET /posts?id_ne=1

Add _like to filter (RegExp supported)

GET /posts?title_like=server

Full-text search

Add q

GET /posts?q=internet

Relationships

To include children resources, add _embed

GET /posts?_embed=comments
GET /posts/1?_embed=comments

To include parent resource, add _expand

GET /comments?_expand=post
GET /comments/1?_expand=post

To get or create nested resources (by default one level, add routes for more)

GET  /posts/1/comments
POST /posts/1/comments

Database

GET /db

Homepage

Returns default index file or serves ./public directory

GET /

Extras

Static file server

You can use JSON Server to serve your HTML, JS and CSS, simply create a ./public directory or use --static to set a different static files directory.

mkdir public
echo 'hello world' > public/index.html
json-server db.json

json-server db.json --static ./some-other-dir

You may also have json-server pass an options object to express.static by adding a js or json file via --staticOptions.

// my-static-options.js
module.exports = {
  setHeaders: (res, path, stat) => {
    if (path.endsWith('login')) {
      res.header('Content-Type', 'text/html; charset=UTF-8');
    }
  }
};

json-server db.json --static ./some-other-dir --staticOptions ./my-static-options

Alternative port

You can start JSON Server on other ports with the --port flag:

$ json-server --watch db.json --port 3004

Access from anywhere

You can access your fake API from anywhere using CORS and JSONP.

Remote schema

You can load remote schemas.

$ json-server http://example.com/file.json
$ json-server http://jsonplaceholder.typicode.com/db

Generate random data

Using JS instead of a JSON file, you can create data programmatically.

// index.js
module.exports = function() {
  var data = { users: [] }
  // Create 1000 users
  for (var i = 0; i < 1000; i++) {
    data.users.push({ id: i, name: 'user' + i })
  }
  return data
}

$ json-server index.js

Tip use modules like faker, casual or chance.

Add routes

Create a routes.json file. Pay attention to start every route with /.

{
  "/api/": "/",
  "/blog/:resource/:id/show": "/:resource/:id"
}

Start JSON Server with --routes option.

json-server db.json --routes routes.json

Now you can access resources using additional routes.

/api/posts
/api/posts/1
/blog/posts/1/show

Add middlewares

You can add your middlewares from the CLI using --middlewares option:

// first.js
module.exports = function (req, res, next) {
  res.header('X-Hello', 'World')
}

json-server db.json --middlewares ./hello.js
json-server db.json --middlewares ./first.js ./second.js

CLI usage

json-server [options] <source>

Options:
  --config, -c         Path to config file           [default: "json-server.json"]
  --port, -p           Set port                                    [default: 3000]
  --host, -H           Set host                               [default: "0.0.0.0"]
  --watch, -w          Watch file(s)                                     [boolean]
  --routes, -r         Path to routes file
  --middlewares, -m    Paths to middleware files                           [array]
  --static, -s         Set static files directory
  --staticOptions -so  Set static options file
  --read-only, --ro    Allow only GET requests                           [boolean]
  --no-cors, --nc      Disable Cross-Origin Resource Sharing             [boolean]
  --no-gzip, --ng      Disable GZIP Content-Encoding                     [boolean]
  --snapshots, -S      Set snapshots directory                      [default: "."]
  --delay, -d          Add delay to responses (ms)
  --id, -i             Set database id property (e.g. _id)         [default: "id"]
  --quiet, -q          Suppress log messages from output                 [boolean]
  --help, -h           Show help                                         [boolean]
  --version, -v        Show version number                               [boolean]

Examples:
  json-server db.json
  json-server file.js
  json-server http://example.com/db.json

https://github.com/typicode/json-server

You can also set options in a json-server.json configuration file.

{
  "port": 3000
}

Module

If you need to add authentication, validation, or any behavior, you can use the project as a module in combination with other Express middlewares.

Simple example

// server.js
var jsonServer = require('json-server')
var server = jsonServer.create()
var router = jsonServer.router('db.json')
var middlewares = jsonServer.defaults()

server.use(middlewares)
server.use(router)
server.listen(3000, function () {
  console.log('JSON Server is running')
})

$ node server.js

For an in-memory database, you can pass an object to jsonServer.router(). Please note also that jsonServer.router() can be used in existing Express projects.

Custom routes example

Let's say you want a route that echoes query parameters and another one that set a timestamp on every resource created.

var jsonServer = require('json-server')
var server = jsonServer.create()
var router = jsonServer.router('db.json')
var middlewares = jsonServer.defaults()

// Set default middlewares (logger, static, cors and no-cache)
server.use(middlewares)

// Add custom routes before JSON Server router
server.get('/echo', function (req, res) {
  res.jsonp(req.query)
})

server.use(function (req, res, next) {
  if (req.method === 'POST') {
    req.body.createdAt = Date.now()
  }
  // Continue to JSON Server router
  next()
})

// Use default router
server.use(router)
server.listen(3000, function () {
  console.log('JSON Server is running')
})

Access control example

var jsonServer = require('json-server')
var server = jsonServer.create()
var router = jsonServer.router('db.json')
var middlewares = jsonServer.defaults()

server.use(middlewares)
server.use(function (req, res, next) {
 if (isAuthorized(req)) { // add your authorization logic here
   next() // continue to JSON Server router
 } else {
   res.sendStatus(401)
 }
})
server.use(router)
server.listen(3000, function () {
  console.log('JSON Server is running')
})

Custom output example

To modify responses, overwrite router.render method:

// In this example, returned resources will be wrapped in a body property
router.render = function (req, res) {
  res.jsonp({
   body: res.locals.data
  })
}

Rewriter example

To add rewrite rules, use jsonServer.rewriter():

// Add this before server.use(router)
server.use(jsonServer.rewriter({
  '/api/': '/',
  '/blog/:resource/:id/show': '/:resource/:id'
}))

Mounting JSON Server on another endpoint example

Alternatively, you can also mount the router on /api.

server.use('/api', router)

Deployment

You can deploy JSON Server. For example, JSONPlaceholder is an online fake API powered by JSON Server and running on Heroku.

Links

Video

• Creating Demo APIs with json-server on egghead.io

Articles

• Node Module Of The Week - json-server
• Mock up your REST API with JSON Server
• ng-admin: Add an AngularJS admin GUI to any RESTful API
• Fast prototyping using Restangular and Json-server
• Create a Mock REST API in Seconds for Prototyping your Frontend

Third-party tools

• Grunt JSON Server
• Docker JSON Server
• JSON Server GUI
• JSON file generator

License

MIT - Typicode