Want to fit a web server into a speck of dust?
Check out smews ( https://github.com/2xs/smews ) it runs with just 8k of flash and 512 bytes of RAM, supports HTTP 1.1 over TCP/IP, SLIP or others, with both static and dynamic content (GET and POST)
The code is 18 years old and hasn’t moved in 10, A sandbox for budding pentesters ;)