For 10,000 idle WebSocket connections sending one message a minute each, our model prices a VPS at a flat $24 a month, Cloudflare Durable Objects at roughly $32, and Vercel Functions at roughly $149.
Cloudflare's Hibernation API stops billing Durable Object duration once a connection goes idle; Vercel's Provisioned Memory meter bills for a function instance's full lifetime including idle time.
The ranking depends on the workload: a bursty, connection-light workload with little idle time would shrink Vercel's Provisioned Memory bill and could change which platform is cheapest.