[duped]

To do this in assembler you write raw syscalls to bind to open the TCP stream and then accept to handle incoming connections, possibly with fork or clone3 to spawn a process/thread to handle the new connection. None of that requires C programming. HTTP is "just" some text parsing on top of read/write calls to the file descriptor returned by accept. Web sockets are "just" some connection logic on top of HTTP.

A basic implementation of that is totally possible in assembly with no calls to c libraries. Would even be a great project for people to learn some systems programming. Keep in mind, all of these protocols (except maybe web sockets) were designed when programming in assembler was common. There's probably some HTTP implementation in the wild doing the same thing.

That said there's a lot of reasons you probably don't want to do that, HTTP can be subtle and you probably don't want to be doing raw clone3 calls to spawn threads, if you want to be doing thread or process per connection in the first place.