stubkit

Google Play Billing

Google Play RTDN, with purchase state you can trust.

A managed Real-Time Developer Notifications endpoint — Pub/Sub ingestion, service-account lookups against the Play Developer API, idempotent events, and a normalised lifecycle stream that speaks the same shape as Apple and Stripe.

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Self-hosted RTDN is more infra than your app should own

  • You need your own Google Cloud project, Pub/Sub topic, service account, and push endpoint with authenticated HTTPS — just to receive the webhook.
  • The RTDN payload is notification-only; you still have to call the Play Developer API to fetch the authoritative purchase state on every event.
  • Google sends duplicate notifications regularly. Without idempotency, you double-grant and double-revoke entitlements.
  • Subscription state transitions are subtle (onHold vs paused vs inGracePeriod) — mistranslating them produces revenue bugs that are very hard to debug.

What Stubkit handles for you

  • A managed Pub/Sub topic and push endpoint per app — no Google Cloud project required.
  • Authoritative purchase state verified via the Play Developer API on every event, using the service account you upload once.
  • Idempotent ingestion keyed on purchaseToken, with a durable audit log.
  • Normalised lifecycle events (subscription.activated / renewed / canceled / refunded / paused) identical in shape across Apple, Google, and Stripe.
  • Sandbox vs production environment isolation out of the box.

See it in action

Ship the integration in minutes with the Stubkit SDK — the receipt flow, retries, and idempotency are handled server-side.

// Stubkit ingests Google Play RTDN messages through a Pub/Sub push
// subscription, looks up the authoritative purchase state via the Google
// Play Developer API, and emits normalised lifecycle events to your server.

import { Stubkit } from '@stubkit/js';

const stubkit = new Stubkit({ apiKey: process.env.STUBKIT_SECRET_KEY });

// Same handler, same event shape, regardless of whether the purchase
// originated on Apple, Google, or Stripe.
app.post('/webhooks/stubkit', async (req, res) => {
  const event = stubkit.verifyWebhook(req.body, req.headers['stubkit-signature']);

  if (event.type === 'subscription.activated') {
    await grantEntitlement(event.data.user_id, event.data.entitlement);
  } else if (event.type === 'subscription.canceled') {
    await revokeEntitlement(event.data.user_id, event.data.entitlement);
  }
  res.sendStatus(200);
});

Common questions

What is Google Play Real-Time Developer Notifications (RTDN)?+

RTDN is Google Play's push channel for subscription and one-time purchase lifecycle events. Instead of polling the Play Developer API, Google pushes a Pub/Sub message to a topic you own whenever a subscription changes state — renewal, hold, paused, canceled, expired, recovered, or deferred.

Does Stubkit provide its own Pub/Sub topic?+

Yes. Each app gets a managed Pub/Sub subscription URL. Paste the package name and topic ID into the Play Console, and Stubkit's push handler receives every notification directly — no Google Cloud project or service account management on your side.

How is purchase state verified?+

On every RTDN message, Stubkit calls the Google Play Developer API with a per-account service account to fetch the authoritative purchase record. The RTDN payload alone is not treated as authoritative — the subscription state is always reconciled against Google's API response before updating your entitlement.

What about duplicate notifications?+

Every RTDN event is keyed on Google's purchaseToken with a unique constraint, so duplicate messages (which Google regularly sends) are de-duplicated server-side. Your backend never sees the same event twice.

How do subscription pauses and deferrals work?+

Stubkit tracks the full lifecycle — onHold, paused, inGracePeriod, revoked, restarted — and translates it into entitlement-level granted / revoked state with a reason field. You receive a single normalised event per lifecycle transition.

Can I test with the Play Billing Library test tracks?+

Yes. Every Stubkit app has a sandbox environment wired up to internal test tracks, so test subscriptions are processed identically to production but kept in a separate event stream. Switching between environments is a single dashboard toggle.

Ship the integration, not the infrastructure.

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