Must websockets have heartbeats?

Question

When I read about websockets, heartbeats are usually mentioned as a must have. MDN even writes about a special opcode for heartbeats.

But are heartbeats a mandatory part

Answer 1

Pings and Pongs are not mandatory. They are useful, since they allow the detection of dropped connections. (Without some traffic on the wire, there is no way to detect a dropped connection.)

Note that in the browser, WebSocket heartbeats are not accessible. If you require your browser client code to detect dropped connections, then you have to implement hearbeating on the application level.