snac

A simple, minimalistic ActivityPub instance

Features

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
No AI accepted (already covered by previous point)

About

This program runs as a daemon (proxied by a TLS-enabled real httpd server) and provides the basic services for a Fediverse / ActivityPub instance (sharing messages and stuff from/to other systems like Mastodon, Pleroma, Friendica, etc.).

This is not the manual; man pages snac(1) (user manual), snac(5) (formats) and snac(8) (administrator manual) are what you are looking for.

snac stands for Social Networks Are Crap.

Building and installation

This program is written in highly portable C. It uses the __attribute__((__cleanup__)) GNU extension, that is supported at least by the gcc, clang and tcc C compilers. The only external dependencies are openssl and curl.

The source code is available here. Here are some detailed descriptions on how to build and install snac in a set of operating systems:

Debian/Ubuntu

Requirements:

apt install libssl-dev libcurl4-openssl-dev # as root

Build and install:

make
make install # as root

OpenBSD

Requirements:

pkg_add curl

Build and install:

make
make install # as root

FreeBSD

Requirements:

pkg install curl

Build and install:

make
make install # as root

NetBSD

Requirements:

pkgin install curl

Build and install:

make -f Makefile.NetBSD
make -f Makefile.NetBSD install # as root

Illumos / OpenIndiana (2026.04)

Requirements:

sudo pkg install openssl-3
sudo pkg set-mediator -V 3 openssl

Build and install:

make CC=gcc LDFLAGS=-lsocket
sudo make install-illumos

Conditional compilation

From version 2.27, snac includes support for the Mastodon API; if you are not interested on it, you can compile it out by running

make CFLAGS=-DNO_MASTODON_API

If your compilation process complains about undefined references to shm_open() and shm_unlink() (it happens, for example, on Ubuntu 20.04.6 LTS), run it as:

make LDFLAGS=-lrt

If it still gives compilation errors (because your system does not implement the shared memory functions), you can fix it with

make CFLAGS=-DWITHOUT_SHM

From version 2.68, Linux Landlock sandboxing is included (not supported on Linux kernels older than 5.13.0). It's still a bit experimental, so you must compile it in explicitly with

make CFLAGS=-DWITH_LINUX_SANDBOX

From version 2.73, the language of the web UI can be configured; the po/ source subdirectory includes a set of translation files, one per language. After initializing your instance, copy whatever language file you want to use to the lang/ subdirectory of the base directory.

See the administrator manual on how to proceed from here.

Testing via Docker

A docker-compose file is provided for development and testing. To start snac with an nginx HTTPS frontend, run:

docker-compose build && docker-compose up

This will:

Start snac, storing data in data/
Configure snac to listen on port 8001 with a server name of localhost (see examples/docker-entrypoint.sh)
Create a new user testuser and print the user's generated password on the console (see examples/docker-entrypoint.sh)
Start nginx to handle HTTPS, using the certificate pair from nginx-alpine-ssl/nginx-selfsigned.* (see examples/nginx-alpine-ssl/entrypoint.sh)

Links of Interest

Incredibly awesome CSS themes for snac

License

See the LICENSE file for details.

Contributing

See the CONTRIBUTING.md file for details.

Author

grunfink @grunfink@comam.es with the help of others.

Buy grunfink a coffee: https://ko-fi.com/grunfink/

Contribute via LiberaPay: https://liberapay.com/grunfink/