To implement Subscription Linking, a publisher must integrate JavaScript code
to link readers on their publications' websites, and create server-side services
to manage linked readers and their entitlements. Additionally, the API must be
enabled in Google Cloud, and the Google Cloud project must be linked to the
relevant Publisher Center publication.

## Pre-requisites

1. You have a Google Cloud Project account. This may be a previously existing account or a new one.
2. You have a [Publisher Center](https://publishercenter.google.com/) account with your [publication already configured for subscription linking](https://support.google.com/news/publisher-center/answer/13543753).
   1. While Subscription Linking is in Beta, you may need to request that the feature is enabled for your publication. Use this [form to request access](https://support.google.com/news/publisher-center/contact/subscription_linking_default) if it is not already available for your publication.
3. Your publication's [domains have been verified](https://support.google.com/webmasters/answer/9008080#:%7E:text=Open%20Search%20Console%20using%20the,below%20to%20troubleshoot%20the%20issue.) within [Google Search Console](https://search.google.com/search-console/about).

> [!NOTE]
> **Note:** To use unverifiable domains for testing, see instructions under [client-side testing](https://developers.google.com/news/subscription-linking/implementation/link-user-accounts#testing).

## Implementation Steps

In recommended order, these are the steps required to enable Subscription
Linking on your site.

1. Add [structured data markup](https://developers.google.com/news/subscription-linking/implementation/structured-data) to the pages of your site.
2. Create [publisher-provided IDs (PPID)](https://developers.google.com/news/subscription-linking/implementation/ppids) for your readers.
3. Integrate [client-side js](https://developers.google.com/news/subscription-linking/implementation/client-side)for letting readers link their publisher account to their Google Account.
4. Implement a [server-side integration](https://developers.google.com/news/subscription-linking/implementation/server-side) for updating entitlements for readers who have linked their account.

## Best Practices

To maximize reader engagement and account linking conversion rates, review the
[Subscription Linking best practices](https://developers.google.com/news/subscription-linking/implementation/best-practices) for guidance on
re-engagement cooldown logic, automatic and button-triggered invocation
strategies, and messaging.