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    0.17.0 • Public • Published

    JSON Server Node.js CI

    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:


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    Table of contents

    Getting started

    Install JSON Server

    npm install -g json-server

    Create a db.json file with some data

      "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, it's 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 will be ignored. Only a value set in a POST request will 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 return a 2XX status code, but without changes being made to the data.


    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


    Use . to access deep properties

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


    Use _page and optionally _limit to paginate returned data.

    In the Link header you'll get first, prev, next and last links.

    GET /posts?_page=7
    GET /posts?_page=7&_limit=20

    10 items are returned by default


    Add _sort and _order (ascending order by default)

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

    For multiple fields, use the following format:

    GET /posts?_sort=user,views&_order=desc,asc


    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

    Works exactly as Array.slice (i.e. _start is inclusive and _end exclusive)


    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


    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 custom routes for more)

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


    GET /db


    Returns default index file or serves ./public directory

    GET /


    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

    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
    $ json-server

    Generate random data

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

    // index.js
    module.exports = () => {
      const data = { users: [] }
      // Create 1000 users
      for (let 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, Chance or JSON Schema Faker.


    There are many ways to set up SSL in development. One simple way is to use hotel.

    Add custom routes

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

      "/api/*": "/$1",
      "/:resource/:id/show": "/:resource/:id",
      "/posts/:category": "/posts?category=:category",
      "/articles\\?id=:id": "/posts/:id"

    Start JSON Server with --routes option.

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

    Now you can access resources using additional routes.

    /api/posts # → /posts
    /api/posts/1  # → /posts/1
    /posts/1/show # → /posts/1
    /posts/javascript # → /posts?category=javascript
    /articles?id=1 # → /posts/1

    Add middlewares

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

    // hello.js
    module.exports = (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>
      --config, -c       Path to config file           [default: "json-server.json"]
      --port, -p         Set port                                    [default: 3000]
      --host, -H         Set host                             [default: "localhost"]
      --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
      --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"]
      --foreignKeySuffix, --fks  Set foreign key suffix, (e.g. _id as in post_id)
                                                                     [default: "Id"]
      --quiet, -q        Suppress log messages from output                 [boolean]
      --help, -h         Show help                                         [boolean]
      --version, -v      Show version number                               [boolean]
      json-server db.json
      json-server file.js

    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

    $ npm install json-server --save-dev
    // server.js
    const jsonServer = require('json-server')
    const server = jsonServer.create()
    const router = jsonServer.router('db.json')
    const middlewares = jsonServer.defaults()
    server.listen(3000, () => {
      console.log('JSON Server is running')
    $ node server.js

    The path you provide to the jsonServer.router function is relative to the directory from where you launch your node process. If you run the above code from another directory, it’s better to use an absolute path:

    const path = require('path')
    const router = jsonServer.router(path.join(__dirname, 'db.json'))

    For an in-memory database, simply 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.

    const jsonServer = require('json-server')
    const server = jsonServer.create()
    const router = jsonServer.router('db.json')
    const middlewares = jsonServer.defaults()
    // Set default middlewares (logger, static, cors and no-cache)
    // Add custom routes before JSON Server router
    server.get('/echo', (req, res) => {
    // To handle POST, PUT and PATCH you need to use a body-parser
    // You can use the one used by JSON Server
    server.use((req, res, next) => {
      if (req.method === 'POST') {
        req.body.createdAt =
      // Continue to JSON Server router
    // Use default router
    server.listen(3000, () => {
      console.log('JSON Server is running')

    Access control example

    const jsonServer = require('json-server')
    const server = jsonServer.create()
    const router = jsonServer.router('db.json')
    const middlewares = jsonServer.defaults()
    server.use((req, res, next) => {
     if (isAuthorized(req)) { // add your authorization logic here
       next() // continue to JSON Server router
     } else {
    server.listen(3000, () => {
      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 = (req, res) => {

    You can set your own status code for the response:

    // In this example we simulate a server side error response
    router.render = (req, res) => {
        error: "error message here"

    Rewriter example

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

    // Add this before server.use(router)
      '/api/*': '/$1',
      '/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)



    Returns an Express server.


    Returns middlewares used by JSON Server.

    • options
      • static path to static files
      • logger enable logger middleware (default: true)
      • bodyParser enable body-parser middleware (default: true)
      • noCors disable CORS (default: false)
      • readOnly accept only GET requests (default: false)


    Returns JSON Server router.


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




    Third-party tools





    npm i json-server

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    • typicode