Buzzrelay

What is Buzzrelay?

Buzzrelay is a follow-only ActivityPub relay, written in Rust, that connects to Mastodon’s streaming API and rebroadcasts matching posts to servers that subscribe. Instead of firehosing an entire network, it lets a fediverse server follow specific hashtags or specific instances and pull only that content into its federated timeline.

What is Buzzrelay best for?

Buzzrelay is best for admins of small or new Mastodon (or Pleroma/Akkoma) instances whose federated timeline feels empty because federation only surfaces what local users already follow. Subscribing to a few hashtag or instance relays fills that timeline with relevant public posts. Most people use the free hosted instance at relay.fedi.buzz and never run it themselves.

What can Buzzrelay do?

• Tag relays — follow a hashtag by adding a URL like https://relay.fedi.buzz/tag/rust, and matching public posts flow into your instance.
• Instance relays — mirror all public posts from a domain, e.g. https://relay.fedi.buzz/instance/mastodon.social.
• Smart digit handling — following #dd also captures numbered variants like #dd1302, so you don’t miss tag spin-offs.
• Streaming firehose — connects to Mastodon’s streaming API and also serves the aggregated firehose back out through a streaming API of its own.
• Blocklist safety — blocks instances on the Garden Fence blocklist, but does no manual content filtering of its own.
• Broad compatibility — works with any ActivityPub server that supports relays, including Mastodon, Pleroma, and Akkoma.
• Self-host paths — build with cargo build --release or deploy via the included NixOS/Flakes module.

Where does Buzzrelay fall short?

• It’s one-directional. Buzzrelay is a follow-only relay: it pushes matching public posts into your timeline but doesn’t broadcast your instance’s own posts outward. If you want a classic bidirectional relay to boost your server’s reach, this isn’t it.
• Instance relays can flood you. Subscribing to a busy hashtag or a large instance can swamp your federated timeline and storage. For heavy volume the project itself recommends consuming its firehose streaming API rather than subscribing to thousands of tags.
• Self-hosting is a niche path. Running your own needs the Rust toolchain, a PostgreSQL database, an RSA keypair, and a config.yaml, with first-class docs aimed at NixOS. The maintainer explicitly steers most people to the public instance instead.

Is Buzzrelay free?

Yes — Buzzrelay is free and open source under the AGPL-3.0 license. The public instance at relay.fedi.buzz is free to use, and self-hosting is free too (you supply the server and PostgreSQL database). There is no paid tier or commercial hosted plan.

FAQ

Is Buzzrelay open source? Yes. Buzzrelay is licensed under AGPL-3.0 and written in Rust, with its source on GitHub.

Do I need to self-host Buzzrelay? No. The maintainer runs a free public instance at relay.fedi.buzz — add a tag or instance relay URL in your server’s admin panel and you’re done. Self-hosting is only for people who want to run their own.

Which servers work with Buzzrelay? Any ActivityPub server that supports relays, including Mastodon, Pleroma, and Akkoma. You paste the relay URL into your instance’s relay settings and enable it.

What do I need to run it myself? A Rust build environment (cargo), a PostgreSQL database, an RSA keypair for signing, and a config.yaml. A NixOS module is provided for Flakes users.