[userbinator]

The only real tip i have is to byte length encode variable length requests, because scanning strings sucks.

This is really, really good advice to use whenever possible: it means clients can determine apriori how much data they need to read, and perhaps decide whether the length is valid and/or allocate sufficient memory. One of my annoyances with the traditional "almost-text-based" protocols like HTTP, FTP, SMTP, etc. is that parsing them is not trivial and often you need to keep reading until you hit the delimiter or reach an internal limit. In contrast, "read a length, then read length bytes" makes for simple and efficient implementation.

There are certainly cases when the amount of data cannot be determined ahead of time, and in those cases I'd suggest chunked-length-prefixing; delimiters are really a method of last resort.