# Tierux > Tierux is an MCP-first, server-side purchase-verification and entitlement platform for Google Play and Apple App Store. It verifies in-app purchases server-side and exposes the result as queryable entitlements over a REST API, so apps can check access without embedding store secrets on-device. AI coding agents configure Tierux products, entitlements, and paywalls over MCP; developer-console steps remain manual, including App Store Connect product and notification setup. Pricing is flat, not a cut of revenue: Free for up to 500 active subscribers, Pro at $39/mo including 1,000 active subscribers (then +$30 per additional 1,000), and Scale at $199/mo with the same overage terms. Google Play verification and webhooks are the most mature path today; Apple App Store support is implemented with limitations — see https://tierux.com/docs-platform-support. Complete docs in one file: https://tierux.com/llms-full.txt ## Docs - [Getting started](https://tierux.com/docs): Use MCP for Tierux-side product, entitlement, and paywall configuration; App Store Connect product and notification setup remains manual before SDK integration. - [Client authentication](https://tierux.com/docs-client-auth): Client-route trust tiers, opaque user IDs, Firebase ID token and App Check enforcement, rate limits, and plan serving behavior. - [Real-time developer notifications](https://tierux.com/docs-rtdn): Set up and handle Google Play real-time developer notifications — Pub/Sub configuration, JWT validation, and entitlement state updates. - [StoreKit 2 verification](https://tierux.com/docs-storekit-verification): How Tierux verifies Apple App Store purchases via StoreKit 2 JWS, including certificate chain validation and entitlement normalization. - [Purchase token validation](https://tierux.com/docs-purchase-token-validation): How Tierux handles purchase token security — hashing for dedup, encryption for refresh, and no raw token storage on disk. - [Webhooks](https://tierux.com/docs-webhooks): Configure and handle webhooks — RTDN, App Store Server Notifications, and custom webhook endpoints for subscription lifecycle events. - [Error codes](https://tierux.com/docs-error-codes): API error codes and troubleshooting, with resolution steps for each error type. - [MCP setup](https://tierux.com/docs-mcp-setup): Connect your AI coding agent to the Tierux MCP server — step-by-step guide for Claude Code, Cursor, and Codex. Claude Code users can install the plugin instead (`/plugin marketplace add tierux-ai/tierux` then `/plugin install tierux@tierux`), which bundles the MCP server, a billing skill, and setup prompts; Codex and Cursor users paste the AGENTS.md block from that page. - [Client SDKs](https://tierux.com/docs-sdks): Android SDK (Maven), iOS Swift SDK (SPM source), and REST-first framework guides for React Native, Flutter, TypeScript, and Expo. ## Product - [Server-side entitlements](https://tierux.com/feature/server-side-entitlements): Verify and gate features server-side — no client API keys, one REST call per entitlement check. - [Purchase verification](https://tierux.com/feature/purchase-verification): Server-side purchase verification for Google Play and Apple; returns normalized entitlement state. - [Entitlement mapping](https://tierux.com/feature/entitlement-mapping): Map store products to entitlement IDs — one API to check access across platforms. - [RTDN webhooks](https://tierux.com/feature/rtdn-webhooks): Auto-process Google Play real-time developer notifications server-side — renewals, expiries, cancellations. - [MCP setup](https://tierux.com/feature/mcp-setup): Configure Tierux products, entitlements, and paywalls via MCP; required Google Play Console and App Store Connect steps remain manual. - [Pricing](https://tierux.com/pricing): Flat monthly fee plus subscriber overage — Free, Pro ($39/mo), and Scale ($199/mo). - [Security](https://tierux.com/security): How Tierux protects purchase data — server-side verification, encrypted token storage, no client API key on device. - [Support](https://tierux.com/support): How to get help — email support, the docs and error-code reference, and where to report Tierux MCP plugin issues. ## Comparisons - [Tierux vs RevenueCat](https://tierux.com/vs/revenuecat): AI-agent/MCP-native setup and flat active-entitlement pricing vs a mature, large-scale, revenue-share platform. - [Tierux vs Adapty](https://tierux.com/vs/adapty): AI-agent/MCP-native setup and flat active-entitlement pricing vs an experimentation- and analytics-heavy subscription platform. - [Tierux vs Superwall](https://tierux.com/vs/superwall): AI-agent/MCP-native setup and flat entitlements pricing vs a paywall infrastructure platform often paired with RevenueCat. - [Tierux vs Qonversion](https://tierux.com/vs/qonversion): AI-agent/MCP-native setup and flat pricing vs an analytics-heavy subscription platform with revenue-share pricing. - [Tierux vs Apphud](https://tierux.com/vs/apphud): AI-agent/MCP-native setup and flat active-entitlement pricing vs an iOS-first receipt validation platform with open-source SDKs. - [Tierux vs Glassfy](https://tierux.com/vs/glassfy): AI-agent/MCP-native setup and flat active-entitlement pricing vs an open-source, SMB-focused subscription platform. - [Tierux vs Nami](https://tierux.com/vs/nami): AI-agent/MCP-native setup and flat active-entitlement pricing vs a paywall CMS with ML optimization. - [Tierux vs Purchasely](https://tierux.com/vs/purchasely): AI-agent/MCP-native setup and flat pricing vs a no-code paywall builder with revenue-share pricing. - [Tierux vs Stripe Billing](https://tierux.com/vs/stripe-billing): Stripe Billing runs web and SaaS subscriptions; in-app digital goods generally must use store billing, which Tierux verifies server-side. - [RevenueCat alternatives](https://tierux.com/revenuecat-alternatives): Compare Tierux, Adapty, Superwall, Qonversion, Apphud, and Glassfy — pricing, features, and fit. ## Guide - [Server-side purchase verification & entitlements guide](https://tierux.com/guide/server-side-verification): The complete guide to turning a purchase token into a trustworthy entitlement — why client-side checks fail, purchase token hashing and encryption, the entitlement state machine, RTDN/App Store Server Notifications, and mapping store products to entitlements. - [Server-driven paywalls & win-back guide](https://tierux.com/guide/paywalls-and-win-back): The complete guide to running paywalls from server-side config — why paywalls should be server-driven, packages and Play-owned prices, cancellation win-back with RTDN (implemented for Google Play; not yet on the App Store), and measuring and shipping paywall changes. See [platform support](https://tierux.com/docs-platform-support) for per-feature status. - [Google Play subscription lifecycle guide](https://tierux.com/guide/subscription-lifecycle): How Google Play subscription states become entitlement state — how Play reports state (subscriptionsv2 query vs RTDN), grace period, account hold and billing retry, plan changes with linkedPurchaseToken, and refunds, revocation and voided purchases. Apple App Store support is implemented with limitations — see [platform support](https://tierux.com/docs-platform-support) for per-feature status. ## Reference - [Glossary](https://tierux.com/glossary): Quick definitions of purchase verification, StoreKit 2, RTDN, entitlements, MRR, churn, ARPU, LTV, paywalls, and more. - [Blog](https://tierux.com/blog): Practical guides on in-app purchase verification, Google Play billing migration, MCP agent setup, and subscription app economics. - [Tools](https://tierux.com/tools): Free interactive calculators for subscription app developers — compare app store fees and billing infrastructure costs.