Ship Real-Time Chat That Scales to Millions of Messages

From one-on-one messaging to group channels with file sharing, Bookuvai builds chat systems that are fast, reliable, and ready for production traffic.

Feature: Real-Time Chat

Real-time chat keeps users engaged and enables instant communication within your application. A production-ready chat system requires persistent WebSocket connections, message delivery guarantees, presence indicators, and offline sync. Bookuvai builds chat features that feel instant while handling edge cases like reconnection, message ordering, and moderation at scale.

Benefits

  • Instant Message Delivery: Sub-100ms message latency with WebSocket connections, automatic reconnection, and offline message queuing for seamless user experience.
  • Rich Media Support: Share images, files, links with auto-preview, code snippets, and emoji reactions. All media is optimized and CDN-served.
  • Presence & Typing Indicators: Real-time online/offline status, last-seen timestamps, and typing indicators that make conversations feel alive.
  • Scalable Architecture: Horizontally scalable with Redis Pub/Sub or managed services, supporting thousands of concurrent connections per server instance.

How It Works

  1. Chat Architecture Design: Define channel types, message retention policies, and real-time requirements to select the optimal WebSocket or managed chat solution.
  2. Backend Implementation: Build message APIs, WebSocket handlers, channel management, and persistent message storage with proper indexing.
  3. Frontend Chat UI: Implement conversation lists, message threads, infinite scroll history, and responsive layouts for desktop and mobile.
  4. Real-Time Features: Add typing indicators, read receipts, online presence, push notification triggers, and unread message counts.
  5. Moderation & Safety: Implement message filtering, user blocking, report/flag workflows, and optional AI-powered content moderation.
  6. Load Testing & Optimization: Stress test with simulated concurrent connections, optimize message fanout, and verify delivery guarantees under load.

Technology Options

  • Socket.io + Redis: Event-driven WebSocket library with built-in rooms, namespaces, and Redis adapter for horizontal scaling across multiple server instances. (Best for: Custom chat with full control over features and data)
  • Firebase Realtime / Firestore: Google-managed real-time database with automatic sync, offline support, and security rules. No WebSocket server to maintain. (Best for: MVPs and mobile apps that need chat up and running quickly)
  • Stream Chat: Managed chat API with pre-built React/React Native components, moderation tools, and enterprise-grade SLAs. (Best for: Teams that want a polished chat UI with minimal custom development)

Estimated Hours

Simple: 15-25 hours | Moderate: 25-50 hours | Complex: 50-100 hours

Frequently Asked Questions

Can you build chat with end-to-end encryption?
Yes. We implement E2E encryption using the Signal Protocol or libsodium, ensuring that messages are encrypted on the sender's device and only decrypted on the recipient's device. Server-side storage contains only ciphertext.
How do you handle message delivery when users are offline?
Messages are persisted server-side and queued for delivery. When the user reconnects, missed messages are synced in order. We also trigger push notifications for new messages while the app is in the background.
Can chat support file and image sharing?
Absolutely. We implement direct upload to S3/Cloud Storage with automatic thumbnailing, virus scanning, and CDN delivery. File messages include preview cards with download links.