This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.

The json() method of the Body mixin takes a Response stream and reads it to completion. It returns a promise that resolves with an object literal containing the JSON data.


response.json().then(function(json) {
  // do something with your JSON




A promise that resolves with an object literal containing the JSON data.


In our fetch json example (run fetch json live), we create a new request using the Request.Request constructor, then use it to fetch a .json file. When the fetch is successful, we read our JSON out of the response using json(), then read values out of the JSON as you'd expect and insert them into list items to display our product data.

var myList = document.querySelector('ul');

var myRequest = new Request('products.json');

fetch(myRequest).then(function(response) {
  return response.json().then(function(json) {
    for(i = 0; i < json.products.length; i++) {
      var listItem = document.createElement('li');
      listItem.innerHTML = '<strong>' + json.products[i].Name + '</strong> can be found in ' + json.products[i].Location + '. Cost: <strong>£' + json.products[i].Price + '</strong>';


Specification Status Comment
The definition of 'json()' in that specification.
Living Standard  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42 [1]
39 (39) [2] Not supported

29 [3]

Not supported
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support Not supported Not supported Not supported Not supported Not supported Not supported Not supported

[1] Behind a preference in version 41.

[2] Behind a preference starting with version 34.

[3] Behind a preference in version 28.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API BODY Experimental Fetch JSON Method Reference