[mythz]

We use SSE for our APIs Server Events feature https://docs.servicestack.net/server-events with C#, JS/TypeScript and Java high-level clients.

It's a beautifully simple & elegant lightweight push events option that works over standard HTTP, the main gotcha for maintaining long-lived connections is that server/clients should implement their own heartbeat to be able to detect & auto reconnect failed connections which was the only reliable way we've found to detect & resolve broken connections.

[dabeeeenster]

"the main gotcha for maintaining long-lived connections is that server/clients should implement their own heartbeat to be able to detect & auto reconnect failed connections"

That sounds like a total nightmare!

[ec109685]

Definitely needed. That would be true for all long lived connection protocols in order to detect connection interruptions in a timely fashion.

[easrng]

Though in JS an EventSource does automatically try to reconnect once it notices the connection is dropped, unlike a WebSocket.

[mythz]

It's not good enough in our experience, EventSource can still think it's connected when the server can no longer push data onto it. The periodic heartbeat to verify messages can still be sent on the connection is the only reliable way we've found to detect & autoretry failed connections.