[stichers]

Thanks for posting this. Full disclosure: I'm the author. I also work for Ably, which is what the post is about, and I'm a content writer so there is inescapably some marketing in it.

But I hope it's valid because, if you try to build a multi-region system for low-latency data transfer across regions, there are issues like discovery and synchronisation to consider.

I think it may be interesting to see how Ably is architected so its pub/sub messaging is realtime and reliable.

For example, how do the EC2 instances in one region find those in another? How does a published message in one region get to a client subscriber in another?