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Generate fake JSON data with Faker.

grunt-faker Build Status

Grunt task for specifying the shape of a JSON object with a basic tag syntax, then generating that object with the Faker library. Each time the task is run the data will look slightly different - making it easy to test against dynamic, ever-changing data scenarios (like the real world!).

Getting Started

This plugin requires Grunt ~0.4.4

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-faker --save-dev

One the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:


The "faker" task


In your project's Gruntfile, add a section named faker to the data object passed into grunt.initConfig().

  faker: {
    my_task: {
      options: {
        jsonFormat: "json/test_all.json",
        out: 'tmp/test_all.json'
    my_other_task: {
      options: {
        jsonFormat: "json/example.json",
        out: ['tmp/example1.json', 'tmp/example2.json']


Only two options here, both are required.


Type: String

A string value that is a path to a JSON file with the desired format.


Type: String|Array

A string value or an array of string values, that is a path to the resulting JSON output file(s).

JSON format

To choose how the output JSON will look, a double curly-bracket syntax is used to identify Faker API methods. To prefix or postfix values you just add them before or after the curly-bracket. The JSON format below could be used to generate a fake customer data object. The strings ("id", "firstName", etc) will always remain static, while the object values will be randomly generated each time the task is run. If options.out is an array, the values will be randomly generated for each file.

Example JSON format file

  "customers" : [
      "id" : "{{random.number(999999)}}",
      "name" : {
          "first" : "{{Name.firstName}} Hubert",
          "last" : "{{Name.lastName}}"
      "address" : {
        "streetAddress" : "{{Address.streetAddress}}",
        "city" : "{{}}",
        "state" : "{{Address.usState}}",
        "zip" : "{{Address.zipCode}}"

Outputs as:

  "customers": [
      "id": 110021,
      "name": {
        "first": "Emerald Hubert",
        "last": "Hintz"
      "address": {
        "streetAddress": "0922 Huels Inlet",
        "city": "Barneyberg",
        "state": "New Hampshire",
        "zip": "22819"


In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

Release History

  • 2014-04-25   v0.2.0   Support for writing JSON data into multiple files and pre/post fixing values, updated dependencies, unit tests
  • 2013-05-12   v0.1.0   Initial release