Another important point is WebSockets can pass through intermediaries (proxies), so it may span multiple TCP connections. As a result TCP keep alive by itself isn't enough. By sending a PING, that web socket frame passes through multiple TCP connections through intermediaries refreshing them

Troubleshooting Backend Course: TROUBLE-FALL25
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Realtime Backends Course: REALTIME-FALL25
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Please note that the Fundamentals of Backend Engineering is an intermediate course that requires some prerequisites such as networking and operating systems fundamentals which I also offer as part of the intermediate backend engineering bundle. You can find this on my website.

And finally the real-time backend systems, my newest course, building backend applications is interesting, building a realtime one is twice is challenging and interesting.

In the Backend Troubleshooting course (and also my favorite) you get to find issues with slow performance, unexpected bugs, and identify exactly where the trouble with performance toolings.

1- Fundamentals of Backend Engineering
2- Troubleshooting Backend Systems
3- Real-Time Backend Systems with WebSockets

The backend course introduces you to the common backend design patterns and how it interacts with both the OS and network to receive requests, process and write responses.

Instead of using a fixed size header for the payload length, the designer used a 7bit indicator to indicate how much bytes will be used.

If payload <= 125, 7 bit should be enough
If payload > 125 & < 65,536 use the next two bytes as length
If payload > 65,536 use the next 8 bytes as length