The Tierux blog
Practical guides on in-app purchase verification, Google Play billing migration, MCP agent setup, and the economics of running subscription apps.
The complete guide to server-side purchase verification & entitlements
The long-form version of our verification coverage: purchase token handling, the entitlement state machine, store notifications, and mapping products to entitlements — five chapters, one problem each.
5-chapter guide
linkedPurchaseToken: how Google Play plan changes really work
When a subscriber upgrades, downgrades, or resubscribes, Play issues a new purchase token linked to the old one. Miss the link and you grant double entitlements.
August 27, 2026 · 6 min read
Purchase tokens are credentials. Treat them like it.
Why raw purchase tokens should never sit in your database, and the hash-for-dedup, encrypt-for-reuse pattern that avoids replay and cross-user redemption risk.
August 27, 2026 · 6 min read
RTDN vs polling: reacting to subscription changes in seconds
Client-side checks only run when the app opens. Real-Time Developer Notifications push renewals, cancellations, and grace periods to your server within seconds instead.
August 27, 2026 · 6 min read
Win-back offers on Google Play: recovering cancelled subscribers server-side
How cancelled-but-not-expired entitlement state identifies win-back candidates, and how offer tokens are applied — implemented for Google Play today; it is not implemented for the App Store.
August 27, 2026 · 5 min read
Setting up MCP for AI agent billing
How to connect the Tierux MCP server to your AI coding agent and let it wire up your entire subscription stack in one prompt.
June 28, 2026 · 5 min read
Server-side purchase verification: the definitive guide
Why client-side verification is advisory at best, how server-side verification actually works, and the common pitfalls when building it yourself.
June 26, 2026 · 8 min read
Migrating to Google Play Billing 7: what changed
The key differences in Billing Library 7, how to handle the new subscription lifecycle APIs, and what breaks when you migrate.
June 24, 2026 · 6 min read
No revenue tax: how app store fees compound
Apple and Google take 15-30%. Revenue-share billing tools take another ~1%. Here is how that compounds and why flat-fee pricing changes the math.
June 22, 2026 · 7 min read
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