> Deprecated:
> Product subscription app extensions won't be supported as of December 3, 2025. You should migrate existing product subscription app extensions to [purchase options extensions](/docs/apps/build/purchase-options/purchase-options-extensions).


Learn about the APIs provided to extension points:

<ul>
<li><strong><a href="/docs/api/product-subscription-extensions/api/layoutapi">LayoutApi</a></strong>: Adjust your content based on the user's screen size.</li>
<li><strong><a href="/docs/api/product-subscription-extensions/api/localeapi">LocaleApi</a></strong>: Access a merchant’s current locale to internationalize your extension content.</li>
<li><strong><a href="/docs/api/product-subscription-extensions/api/sessiontokenapi">SessionTokenApi</a></strong>: Get a fresh session token for communication with your app's backend service.</li>
<li><strong><a href="/docs/api/product-subscription-extensions/api/toastapi">ToastApi</a></strong>: Provide quick, at-a-glance feedback on the outcome of an action.</li>
</ul>