This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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.


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.

Return value

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 calls 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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support44116392 No313 No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support441441 No39313 No4.0

1. Requires HTTPS from version 46.

2. Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).

3. Requires HTTPS from version 33.

See also

Document Tags and Contributors

Last updated by: ricea,