7 WebSocket/PubSub Providers Ranked

1. Ably — best managed pub/sub at scale
2. PubNub — solid real-time platform
3. Pusher — easiest DX for channels
4. Socket.io — self-hosted, most flexible
5. AWS AppSync — managed GraphQL subscriptions
6. Cloudflare Workers + Durable Objects — edge-native real-time
7. Self-hosted Valkey/Redis — cheapest at scale, most operational work

Stock Picks's feed runs on a self-hosted Valkey sidecar — at our scale it's the cheapest option, and the control is worth the ops cost. Above ~50k connections, Ably starts looking smart.