Customize user experience for known customers

Use a Shared Storage worklet to identify known customers.

The Shared Storage API is a Privacy Sandbox proposal for general purpose, cross-site storage, which supports many possible use cases. One example is identifying known customers, which is available to test in Chrome 104.0.5086.0 and later.

You can store whether the user has registered on your site into Shared Storage, then render a separate element based on whether the user's stored status (is the user a "known" customer).

Set known customers

To experiment with identifying known customers in Shared Storage, confirm you're using Chrome 104.0.5086.0 or later. Enable all the Ad privacy APIs under chrome://settings/adPrivacy.

You can also enable Shared Storage with the --enable-features=PrivacySandboxAdsAPIsOverride,OverridePrivacySandboxSettingsLocalTesting,SharedStorageAPI,FencedFrames flag in the command line.

Experiment with code samples

You may want to render a different element based on whether the user was seen on a different site. For example, a payment provider may want to render a "Register" or "Buy now" button based on whether the user has registered at the payment provider's site. Shared storage can be used to set the user's status and customize their user experience based on that status.

In this example:

  • known-customer.js is embedded in a frame. This script sets the options for which button should be displayed on a site, "Register" or "Buy now."
  • known-customer-worklet.js is the shared storage worklet that determines if the user is known. If the user is known, the information is returned. If the user is unknown, that information is returned to display the "Register" button and the user is marked as known for the future.

known-customer.js

// The first URL for the "register" button is rendered for unknown users.
const BUTTON_URLS = [
  { url: `https://${advertiserUrl}/ads/register-button.html` },
  { url: `https://${advertiserUrl}/ads/buy-now-button.html` },
];

async function injectButton() {
  // Load the worklet module
  await window.sharedStorage.worklet.addModule('known-customer-worklet.js');

  // Set the initial status to unknown ('0' is unknown and '1' is known)
  window.sharedStorage.set('known-customer', 0, {
    ignoreIfPresent: true,
  });

  // Run the URL selection operation to choose the button based on the user status
  const fencedFrameConfig = await window.sharedStorage.selectURL('known-customer', BUTTON_URLS, {
    resolveToConfig: true
  });

  // Render the opaque URL into a fenced frame
  document.getElementById('button-slot').src = fencedFrameConfig;
}

injectButton();

known-customer-worklet.js

class SelectURLOperation {
  async run(urls) {
    const knownCustomer = await sharedStorage.get('known-customer');

    // '0' is unknown and '1' is known
    return parseInt(knownCustomer);
  }
}

register('known-customer', SelectURLOperation);

Use cases

All available use cases for Select URL API can be found in this section. We'll continue to add examples as we receive feedback and discover new test cases.

Engage and share feedback

Note that the Select URL API proposal is under active discussion and development and subject to change.

We're eager to hear your thoughts on the Select URL API.

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