Hey, have you tried the new GraphQL subscriptions endpoint?

I've been running it for two weeks with zero downtime. Handles about 12k concurrent connections on a single instance.

Around 480MB for the subscription server. The main bottleneck is the Redis pub/sub layer — you'll want to shard if you go above 50k connections.

Nice. One tip — set the heartbeat interval to 30s instead of the default 15s. Cuts bandwidth in half with no noticeable latency increase.