--- name: tg-miniapp description: Build Telegram Mini Apps without the pain. Includes solutions for safe areas, fullscreen mode, BackButton handlers, sharing with inline mode, position:fixed issues, and React gotchas. Use when building or debugging Telegram Mini Apps, or when encountering issues with WebApp API, safe areas, or sharing. ---

Telegram Mini App Development

Battle-tested solutions for common Telegram Mini App issues.

Quick Reference

Safe Area (Fullscreen Mode)

// Use reactive hook - values are async and context-dependent
const safeArea = useSafeAreaInset(); // from references/hooks.ts
<div style={{ paddingTop: safeArea.top }}>Header</div>

position:fixed Broken

Telegram applies transform to container. Use createPortal:

import { createPortal } from 'react-dom';
createPortal(<Modal />, document.body);

BackButton Not Firing

Use @telegram-apps/sdk, not raw WebApp:

import { onBackButtonClick, showBackButton } from '@telegram-apps/sdk';
onBackButtonClick(handleBack);

Sharing with Inline Mode

1. Enable inline mode: @BotFather → /setinline → select bot
2. Backend calls savePreparedInlineMessage → returns prepared_message_id
3. Frontend calls WebApp.shareMessage(prepared_message_id)

Note: prepared_message_id is single-use — prepare fresh for each share tap. For static content, consider caching images on R2/CDN and preparing per-tap.

React "0" Rendering

// WRONG: renders literal "0"
{count && <span>{count}</span>}

// CORRECT
{count > 0 && <span>{count}</span>}

Detailed Guides

• references/KNOWLEDGE.md — Full knowledge base with all gotchas and solutions
• references/hooks.ts — Copy-paste React hooks (useSafeAreaInset, useFullscreen, etc.)
• references/components.tsx — Ready-to-use components (SafeAreaHeader, DebugOverlay)

Testing Checklist

Before shipping, test:

• [ ] Open from folder (chat list)
• [ ] Open from direct bot chat
• [ ] iOS device
• [ ] Android device
• [ ] Share flow (tap → dismiss → tap again)
• [ ] Share to different chat types (user, group, channel)
• [ ] Back button
• [ ] Scroll with sticky header