Faking is Good: Back-end Data and API Prototyping with Faker.js and JSON-Server

Faking is Good: Back-end Data and API Prototyping with Faker.js and JSON-Server


We are agile! In most of our projects we are asked to develop User Interfaces in parallel to the back-end services and APIs. This gives us the challenge of Implement and Test the User Interfaces without the real and real-like data availability. Not only that, how about the APIs? Can it be faked such that,

  • User Interfaces can be integrated with REST APIs at Day one?
  • These APIs provide interaction points almost similar to what it would be with actual data?
  • The calls can have over the wire such that, we get a feeling of retrieving data from a remote server(that mimics the real-life use-case)
  • Can it be done in few minutes?

For most of the projects where I less worry about the truthfulness of the data but, rest of it matters, I would like to use the combination of these:


Faker.js helps us building massive amount of Fake data in real quick time. Though the data is fake, you can still build the data with the required type, structure with which the User Interfaces can be tested early.

It has got various methods to provide data related to address, finance, commerce, date etc.

JSON Server

JSON Server helps us in getting a full fake REST API with zero coding in less than a minute! It is insanely true. The beauty of it is, it uses a JSON file as a data store which can be built easily with Faker.js.

Showcase: Quick Steps

As we have got a high level introductions to both Faker.js and JSON Server, let us see them coming together to solve the data and API prototype problem, faster.

Create a node project

  • Create a directory with a name of your choice. say, json-faker-server.
  • Change to the directory json-faker-server.
  • Do npm init
  • Answer the questions to create a node project. Now, you must have a file called package.json created.

Install Dependencies

  • Install Faker.js
 npm install faker --save
  • Install JSON Server
 npm install json-server --save

Create a database

We will be creating a database(db.json) using Faker.js.

  • Create a file called index.js at the root of the folder.
  • Create Fake data of your need. In the following example, I have showed how to create user data with the properties make sense to me.
  const faker = require('faker');
  let database = { users: []};
  const threshold = 1000;

  for (let i = 1; i<= threshold; i++) {
    id: i,
    name: faker.name.firstName() + " " + faker.name.lastName(),
    job: faker.name.jobTitle(),
    about: faker.lorem.paragraph(),
    phone: faker.phone.phoneNumber(),
    userName: faker.internet.userName(),
    email: faker.internet.email(),
    salary: "$" + faker.finance.amount() + "M",
    // You can also use faker.image.people() for image
    image: "https://source.unsplash.com/1600x900/?user", 
    country: faker.address.country()

  • In the scripts of package.json add this,
 "generate": "node ./index.js > ./db.json",
  • Now, you can generate 1000 user records(in db.json) just by running this:
 npm run generate

Create the Server and APIs

  • This step is way more simpler. In the scripts of package.json add this,
 "server": "json-server --watch ./db.json"
  • Now, you can start the server using,
 npm run server

You will see the server running on the default port(3000). The API will be available @ localhost:3000/users

API Functions

These are the API endpoints we'll be able to use via JSON REST API server:

  • GET /users for getting the users
  • GET /users/ for getting a single user by id
  • POST /users for creating a new user
  • PUT /users/ for updating a user by id
  • PATCH /users/ for partially updating a user by id
  • DELETE /users/ for deleting a user by id

We can use _page and _limit parameters to get paginated data as well. That is not all, there are options to search, sort, slice etc, without writing a single line of code. See here for more details.

Links and Resources

  • There are ways to deploy and host the JSON Server on Heroku, Now, Azure etc. Here is a great read on how to do it. I have deployed the users API on Heroku. Here it is: json-faker-server.herokuapp.com/users
  • All about Faker.js can be found here.
  • Read about JSON Server from here.
  • All the code examples in this blog post can be found at my GITHub Project.

Hope you enjoyed reading it. That's all for now.

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