This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage 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 specification changes.

The add() method of the Cache interface takes a URL, retrieves it and adds the resulting response object to the given cache. The add() method is functionally equivalent to the following:

fetch(url).then(function (response) {
  if (!response.ok) {
    throw new TypeError('bad response status');
  return cache.put(url, response);

For more complex operations, you'll need to use Cache.put() directly.

Note: add() will overwrite any key/value pair previously stored in the cache that matches the request.

Note: Initial Cache implementations (in both Blink and Gecko) resolve Cache.add, Cache.addAll, and Cache.put promises when the response body is fully written to storage.  More recent spec versions have newer language stating that the browser can resolve the promise as soon as the entry is recorded in the database even if the response body is still streaming in.

Note: As of Chrome 46, the Cache API will only store requests from secure origins, meaning those served over HTTPS.


cache.add(request).then(function() {
  //request has been added to the cache


The request you want to add to the cache. This can be a  Request object or a URL.


A Promise that resolves with void.


Exception Happens when

The URL scheme is not http or https.

The Response status is not in the 200 range (i.e., not a successful response.) This occurs if the request does not return successfully, but also if the request is a cross-origin no-cors request (in which case the reported status is always 0.)


This code block waits for an InstallEvent to fire, then runs waitUntil to handle the install process for the app. This consists of calling to create a new cache, then using Cache.add to add an asset to it.

this.addEventListener('install', function(event) {
  event.waitUntil('v1').then(function(cache) {
      return cache.add('/sw-test/index.html');


Specification Status Comment
Service Workers
The definition of 'Cache' in that specification.
Working Draft Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 46.0 (Yes)[1] No support 24 No support
Require HTTPS 46.0 (Yes)[1] ? ? ?
TypeError if request is not successful (Yes) 47.0 (47.0)[1] (Yes) (Yes) (Yes)
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support (Yes) ? No support ? No support 46.0
Require HTTPS No support No support (Yes) ? ? ? ? 46.0
TypeError if request is not successful (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)

See also

Document Tags and Contributors

 Contributors to this page: bkelly, chrisdavidmills, jpmedley, kscarfone
 Last updated by: bkelly,