Snac (AKA Snac2) is a minimal microblogging ActivityPub instance written in C.

Features (from its Codeberg repo):

• Lightweight, minimal dependencies
• Extensive support of ActivityPub operations, e.g. write public notes, follow users, be followed, reply to the notes of others, admire wonderful content (like or boost), write private messages…
• Multiuser
• Mastodon API support, so Mastodon-compatible apps can be used
• Simple but effective web interface
• Easily-accessed MUTE button to silence morons
• Tested interoperability with related software
• No database needed
• Totally JavaScript-free
• No cookies either
• Not much bullshit