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
- My JSON Server - no installation required, use your own data
See also:
- 🐶 husky - Git hooks made easy
- 🦉 lowdb - local JSON database
- ❌ ✔️ xv - the most minimalist test runner
From generating an API to importing a CSV into postgres, Retool’s range of 20+ developer utilities is a go-to resource when building apps. Check it out now
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- Getting started
- Routes
- Extras
- Links
- License
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 https://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
.
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
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
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 /
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 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 https://example.com/file.json
$ json-server https://jsonplaceholder.typicode.com/db
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.
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
You can add your middlewares from the CLI using --middlewares
option:
// hello.js
module.exports = (req, res, next) => {
res.header('X-Hello', 'World')
next()
}
json-server db.json --middlewares ./hello.js
json-server db.json --middlewares ./first.js ./second.js
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: "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]
Examples:
json-server db.json
json-server file.js
json-server https://example.com/db.json
https://github.com/typicode/json-server
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.
$ 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.use(middlewares)
server.use(router)
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.
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)
server.use(middlewares)
// Add custom routes before JSON Server router
server.get('/echo', (req, res) => {
res.jsonp(req.query)
})
// To handle POST, PUT and PATCH you need to use a body-parser
// You can use the one used by JSON Server
server.use(jsonServer.bodyParser)
server.use((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, () => {
console.log('JSON Server is running')
})
const jsonServer = require('json-server')
const server = jsonServer.create()
const router = jsonServer.router('db.json')
const middlewares = jsonServer.defaults()
server.use(middlewares)
server.use((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, () => {
console.log('JSON Server is running')
})
To modify responses, overwrite router.render
method:
// In this example, returned resources will be wrapped in a body property
router.render = (req, res) => {
res.jsonp({
body: res.locals.data
})
}
You can set your own status code for the response:
// In this example we simulate a server side error response
router.render = (req, res) => {
res.status(500).jsonp({
error: "error message here"
})
}
To add rewrite rules, use jsonServer.rewriter()
:
// Add this before server.use(router)
server.use(jsonServer.rewriter({
'/api/*': '/$1',
'/blog/:resource/:id/show': '/:resource/:id'
}))
Alternatively, you can also mount the router on /api
.
server.use('/api', router)
jsonServer.create()
Returns an Express server.
jsonServer.defaults([options])
Returns middlewares used by JSON Server.
- options
static
path to static fileslogger
enable logger middleware (default: true)bodyParser
enable body-parser middleware (default: true)noCors
disable CORS (default: false)readOnly
accept only GET requests (default: false)
jsonServer.router([path|object])
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.
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