Glad to hear you liked the video, thanks for taking the time to comment and we'll keep that in mind :D

Great to hear that and thanks for commenting. Are you going to build your own horizontally scaling WebSocket feature?

Thanks for the kind words, glad you liked it! Let us know if there's any other topics you'd like to see next.

@@AblyRealtime Load testing using artillery will be a great topic where you not only emit events to server in a loop but also listen to the server sent events at the client side i.e, artillery

Could you please explain how you would do that ? I guess we could have a chat service that create websocket connections, and subscribe/ push to redis. New messages would be pushed to kafka. We would have another service subscribing to kafka queues dedicated to handling messages, saving them to DB and then publishing to redis Then the chat service receives this message and sends it via ws. What do you think ?

Hmm our system process was: ws => Kafka message => consumer to write message to redis and db for recovery. Another Kafka listener that would also send message to ws by looking at redis to find where client was to send back to client.

redis can do pub-sub and can be a DB too.

We're glad you enjoyed it

All very good questions, thanks for sharing! Perhaps for a future video👍🏻

In a typical setup with a load balancer, you wouldn’t communicate directly with individual server instances from the frontend. Rather, you would communicate with the LB, which would handle redirecting your requests to the appropriate instances - Alex

You’re spot-on, except Redis is well-suited for clustering compared to your own WebSocket server.

Thanks so much !

Hey there! Redis is used in this situation more as a cache, optimised brokering the messages with ultra low latency. The classic design to persist messages longterm is to have an additional relational DB as a layer after Redis (to the right in the diagram)

Yes, this would be a recommended design pattern, and has increased security benefits over navigating rooms and servers using naming patterns. Thanks for your question!

@@AblyRealtime I appreciate your reply!

Thanks for the suggestion! We'll keep this in mind for future videos.

You have to set-up a way to provision and shed Redis instances to match scaling demands. Some use-cases will demand a Kubernetes type service to manage the instances, and others a more homegrown solution.

Thanks for your feedback! If you're interested, this is certainly the kind of content we'll consider delving deeper into in the future.

Alex from the video here 👋🏻 That is a good question. WebSockets are a realtime communication protocol that provides a full-duplex communication channel between client and server over a long-lived connection, meanwhile Redis is an in-memory data structure store. Sometimes confusion can arise because Redis does support pub/sub, but that mechanism is primarily designed to handle communication between your app/services and Redis. It's not suitable for realtime interaction between your server and clients (end-users). For example, you'd be hard-pressed to connect to Redis from a browser in a a sensible way but that's exactly what Websockets are designed for.

@@AblyRealtime Thank you for the reply. Websocket for the realtime experience.

This is often not possible with phones or tablets due to constraints from Apple and Android with apps not allowing background WebSocket connections. It is not even possible to send REST https requests to apps running in the background. The only way around is to send a push notification. If the app is running in the foreground indefinitely, the socket connection can stay open.