Azure’s raw WebSocket service against a batteries-included realtime platform: reliability, presence, and the 2 KB metering rule.
Azure Web PubSub is the sibling of Azure SignalR for non-SignalR clients: raw WebSockets, optional pub/sub subprotocols, unit-day pricing. It gives you a scalable socket. Most of what this page compares is how much you build on top of that socket versus what comes built in.
When Foony fits
Reliability by default. Web PubSub connections are fire-and-forget unless clients implement the reliable subprotocol, and the official client SDK wrapping it is JavaScript and C# only, in preview. Foony’s guarantees are on for every client.
History exists. Web PubSub stores no customer data, a client that misses the short redelivery window is disconnected and starts over. Foony replays from storage for up to 30 days.
Presence without webhooks. Web PubSub’s pattern is handling connect and disconnect events on your own server and rebroadcasting counts.
Simpler metering: Web PubSub counts outbound traffic in 2 KB increments and bills webhook calls and even diagnostic logs as messages.
A server-optional architecture. In Web PubSub’s default mode, simple WebSocket clients must have a registered event handler webhook or the service drops the connection.
When Azure Web PubSub fits
You need bring-your-own-protocol sockets, including MQTT 3.1.1 and 5.0 clients (in preview), on Azure.