Want a simpler approach?
The RevenueCat SDK Handbook covers the same topics — with less code and a managed backend.
The Google Play Billing Handbook
A complete guide to implementing in-app purchases and subscriptions on Android from scratch.
Table of contents
Foundations
Chapter 1Chapter 2
Understanding Google Play's Billing System
The big picture: key actors, core vocabulary, product types, and the three pillars of Google Play Billing.
Setting Up Your Environment
Developer account, Play Console, service account keys, Pub/Sub for RTDNs — everything before a single line of code.
Products
Chapter 3Chapter 4
One Time Products
Consumable and non-consumable products: querying, purchasing, server verification, and the acknowledge-or-consume decision.
Subscriptions Deep Dive
The Subscription → Base Plan → Offer hierarchy. Free trials, intro pricing, prepaid plans, and installment subscriptions.
Client-side integration
Chapter 5Chapter 6Chapter 7Chapter 8
Integrating the Play Billing Library
BillingClient setup, connection lifecycle, product queries, and the four builder methods you must call correctly.
The Purchase Flow
End-to-end from launchBillingFlow() to acknowledgement: payment dialog, callbacks, pending purchases, and multi-quantity.
Subscription Upgrades, Downgrades, and Plan Changes
Six replacement modes, proration math, linkedPurchaseToken chains, and choosing the right mode for each scenario.
Error Handling and Retry Strategies
Every BillingResponseCode explained. Simple retry, exponential backoff, and the complete error decision tree.
Server-side
Chapter 9Chapter 10
Backend Architecture for Billing
The 7-step server verification flow: receive token, call the API, check signatures, grant entitlements, acknowledge.
Real Time Developer Notifications (RTDN)
Cloud Pub/Sub setup, all 16+ notification types, idempotent handlers, and the "always call the API" rule.
Subscription lifecycle
Chapter 11Chapter 12Chapter 13Chapter 14
The Subscription State Machine
Seven states (ACTIVE through PENDING), every transition, which states grant access, and queryPurchasesAsync() behavior.
Payment Recovery: Grace Period and Account Hold
Two-stage recovery: grace period with access retained, then account hold with access revoked. Configuration and code.
Cancellations, Pauses, and Winback
Cancellation ≠ immediate revocation. Pause mechanics, restore vs. resubscribe, deferral API, and winback strategies.
Changing Subscription Prices
Opt-in increases, opt-out decreases, legacy price cohorts, migration API, and regional pricing considerations.
Production readiness
Chapter 15Chapter 16Chapter 17
Security and Fraud Prevention
Server-side verification, purchase token obfuscation, Voided Purchases API, and ProGuard/R8 configuration.
Testing Your Integration
License testers, Play Billing Lab, accelerated renewals, 11 test scenarios, and the response code simulator.
Managing Your Product Catalog at Scale
Batch APIs for subscriptions, base plans, offers, and one-time products. Quota tiers, reconciliation, and automation.
Reference
Appendix AAppendix BAppendix CAppendix DAppendix E
Complete RTDN Reference Table
Every RTDN type, payload structure, and required server action on a single reference page.
BillingResult Response Code Reference
All BillingResponseCode values, sub response codes, retry strategies, and the error handling decision tree.
Google Play Developer API Quick Reference
Every endpoint for purchases, subscriptions, catalog management, and voided purchases with key response fields.
Migrating from PBL 7 to PBL 8
Breaking changes, new APIs, deprecations, and a step-by-step migration checklist from PBL 7 to PBL 8.
Subscription State Diagram (Pull Out Reference)
The complete state machine as a pull-out reference: all states, transitions, access rules, and token lifecycle.
What RevenueCat replaces
A side-by-side look at what the SDK handles and what stays your responsibility.
Related resources
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RevenueCat Docs
Full SDK reference, platform guides, and integration walkthroughs for every feature.
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Sub Club Podcast
Insights on subscription app growth, pricing strategies, and retention from industry experts.
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Сat-paywall-compose
Open-source Jetpack Compose paywall example with production-ready code.