SaaS entitlements

const GRACE_DAYS = 14; // your merchant setting

function hasAccess(subscription, now = new Date()) {
  if (subscription.status === "trialing" || subscription.status === "active") {
    return true;
  }
  if (subscription.status === "past_due" && subscription.pastDueSince) {
    const since = new Date(subscription.pastDueSince);
    return now - since < GRACE_DAYS * 86_400_000;
  }
  return false;
}

​

Handle events idempotently

• Events can arrive more than once and out of order. Upsert the subscription by id, and ignore an event whose createdAt is older than the copy you stored.
• Grant access on subscription.created for a trial, and on subscription.created or subscription.renewed for a paid start.
• Re-evaluate access on every subscription.updated, subscription.past_due and subscription.cancelled.
• When in doubt, read GET /subscriptions/:id; it is always current.

​

Which events to store