node package manager

json-server

Serves JSON files through REST routes.

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.

See also:

  • 🏨 hotel - Local domains for everyone and more!
  • 🐶 husky - Git hooks made easy

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 wil result in a 200 OK but without changes being made to the data.
$ npm install -g json-server

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

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

Use . to access deep properties

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

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

Add _sort and _order (ascending order by default)

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

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

Add q

GET /posts?q=internet

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
GET /db

Returns default index file or serves ./public directory

GET /

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

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

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

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

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

You can load remote schemas.

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

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.

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
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
  --static, -s       Set static files directory
  --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:
  bin db.json
  bin file.js
  bin http://example.com/db.json

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

{
  "port": 3000
}

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 (reqres) {
  res.jsonp(req.query)
})
 
server.use(function (reqresnext) {
  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')
})

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 (reqres) {
  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)

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

MIT - Typicode