A follow-only ActivityPub relay that carries supplementary data from other instances to your server.

This project starts as a fork of buzzrelay, and a large part of the content is directly inherited from that project. Many thanks to @Astro for sharing his amazing work.

courier will try its best to carry the following data to your server:

1. Completion: The replies to posts appeared on the global timeline. Most ActivityPub implementations will not proactively fetch replies for posts that originated from other instances. Therefore, users are not guranteed to see all replies to a post, unless all participants are followed by someone in the current server, or jump to the original server to get a complete view. This is the main reason why I develop courier. courier will try to fetch all replies from remotes and send them to the current server, so no need to jump across different instances.
2. Trends: The trending posts on other instances. This feature is designed for small instances that do not have a large number of users, but still want to see what's trending in the Fediverse.

Disclaimer: courier is still working in progress, and I have only tested it on my Misskey instance. If you are experiencing any problems and would like to help with development, please submit an issue!

For instance moderators: All data sent by courier for the Completion feature is wrapped in activities with type ["Announce", "Relay"], which will be translated into retoots or renotes in most implementations. I did not find a more elegant way to do this, so if you do not want your server's timeline to be flooded with retoots, try globally muting actors from courier, or patch the server to recognize the Relay type. I use this patch for my Misskey instance.

NixOS/Flakes users are in luck: not only does this build, it also comes with a NixOS module!

Anyone else installs a Rust toolchain to build with:

cargo build --release

ActivityPub messages are signed using RSA keys. Generate a keypair first:

openssl genrsa -out private-key.pem 4096
openssl rsa -in private-key.pem -pubout -out public-key.pem

Let your config.yaml point there.

Create a PostgreSQL database and user, set them in your config.yaml.

The program will create its schema on start.