## Table of Contents

1. [Overview & Architecture](#overview)
2. [TWA SDK Setup (v3) + v2→v3 Migration](#twa-sdk-setup)
3. [Native Capabilities: CloudStorage, Biometry, Fullscreen, shareStory](#native-capabilities)
4. [initData HMAC Validation](#initdata-validation)
5. [Bot Setup with grammY](#bot-setup-grammy)
6. [Webhook Handlers](#webhook-handlers)
7. [Stars Payments (XTR) — invoice messages & openInvoice](#stars-payments)
8. [Deep Linking](#deep-linking)
9. [Telegram Theme CSS Variables](#theme-css-variables)
10. [MarkdownV2 Escaping](#markdownv2-escaping)
11. [Database Options](#database-options)
12. [Next.js Deployment](#nextjs-deployment)
13. [Security Hardening (serverless-safe rate limiting)](#security)
14. [Complete Example App](#complete-example)
15. [Troubleshooting](#troubleshooting)

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