Google Cloud and Firebase. Free tiers available for experimenting ;) Caddy is very versatile as web server, proxy, load balancer, etc. And plays well with gRPC

Google Cloud and Firebase. Free tiers available for experimenting ;) Caddy is very versatile as web server, proxy, load balancer, etc. And plays well with gRPC. For middleware, golang is enough. Gorilla and go-kit add useful helpers. As far as frontend, I've used Bootstrap, Foundation, etc. But prefer building custom solutions with things like D3.JS and Babylon.JS. Stripe Elements is also really nice. Good luck!