OP here. 1) You’re right, 1 GiB free tier will exhaust fast. Beyond that standard GCP-wide egress rates apply. So if you were using VMs to serve this chatroom,

OP here. 1) You’re right, 1 GiB free tier will exhaust fast. Beyond that standard GCP-wide egress rates apply. So if you were using VMs to serve this chatroom, you'd be paying the same https://cloud.google.com/network-tiers/pricing#premium-pricing https://cloud.google.com/network-tiers/pricing#premium-prici... 2) I think you’re missing out the part that in this setup only 1000 instances connect to Redis (using 1000 connections). We don’t initiate a per-user connection from the backend to Redis. Once a message is pushed to an app instance, the sample app pushes it to all its connected users.