WebSockets are hard to scale, it's true. The stateful connection that makes them so powerful for two-way realtime communication also makes them tricky to load balance efficiently, but that isn't to say it can't be done. In this video, Alex Booker (@CodeCast) from Ably runs you through the technical challenges scaling WebSockets before outlining the patterns used  to scale WebSockets to thousands of concurrent connections and beyond. Theoretically,  the approach to system design outlined in this video can scale to millions of concurrent WebSocket connections in a production environment.

ABOUT ABLY  👋
Ably is an enterprise-grade pub/sub messaging platform. We make it easy to efficiently design, quickly ship, and seamlessly scale critical realtime functionality delivered directly to end-users. Every day, we deliver billions of realtime messages to millions of users for thousands of companies.

TIMESTAMPS ⏰
00:00 Introduction
00:16 Why WebSockets are hard to scale
01:33 Why WebSocket benchmarks are misleading
03:03 Options for scaling WebSockets
03:32 Introduction to vertical scaling
04:14 Challenges with vertical scaling WebSockets
06:30 Horizontal scaling
07:40 Horizontal scaling continued
09:55 Challenges with horizontal scaling WebSockets
11:38 Conclusion

LINKS MENTIONED 🔗
- The WebSocket hand book (free WebSocket book): https://hubs.la/Q01ZQm6Z0
- Guide to HTTP long polling: https://hubs.la/Q01ZQnM20