This form has a randomly created ppid, but can be set by the reader.
<script>
subscriptions.linkSubscriptions({publisherProvidedId: `ppid` });
</script>
<script>
subscriptions.linkSubscriptions({linkTo: [
{ publicationId: 'pubId1', publisherProvidedId: 'ppid1' },
{ publicationId: 'pubId2', publisherProvidedId: 'ppid2' },
…
]});
</script>
basic{
product_id: '{publicationId}:basic',
subscription_token: 'abc1234',
detail: 'This is our basic plan',
expire_time: '2025-07-22T19:25:04.837Z'
}