Snac2 is a lightweight ActivityPub server, it rely on SQLite DB by user and files on disks, that's all. Don't overgrow like some other servers (Pleroma). It is wrote in C language without unfinite libs dependency, so fast, reliable, not a myriad on unreliable/unmaintained/backdoored language modules.
For reference, installed size of Arch Linux binary (daemon and command) for release 2.64 is:
So this can run coupled with nginx on a really light Solar Powered SBC (There are a lot of very efficient and cheap ARM or RISC-V SBC available now).