How to Set Up FediBuzz Relay for Topic-Based Federation

Mastodon relays broadcast public posts from one instance to many others. A standard relay sends all public content from participating servers. This creates noise if you only want posts about a specific subject like photography or Linux. FediBuzz Relay solves this by filtering posts based on hashtags before distributing them. This article explains how to configure FediBuzz Relay so your instance receives only topic-relevant federated content.

What FediBuzz Relay Does and Why Topic-Based Federation Matters

FediBuzz Relay is a Mastodon-compatible relay service that forwards public posts containing specific hashtags. Unlike a standard relay that broadcasts all public toots from every connected server, FediBuzz Relay acts as a filter. It subscribes to your chosen hashtags and delivers only matching posts to your instance. This reduces server storage, bandwidth use, and timeline clutter.

The relay works by receiving public posts from instances that have enabled relay subscription. It then checks each post for the hashtags you selected. If a post lacks any of the tracked tags, it is discarded. The matching posts are sent to your Mastodon server through the standard relay protocol. Your instance treats these posts as if they came from any other federated server.

Prerequisites Before Setting Up the Relay

You need administrator access to your Mastodon instance. The relay setup requires the Relays section under Preferences > Administration. If you run a single-user instance, you are the administrator by default. For multi-user instances, ask your admin to perform these steps. You also need a FediBuzz Relay subscription. Visit the FediBuzz website and create an account if you have not done so. The service offers free and paid tiers based on the number of hashtags you can track.

How Hashtag Filtering Works in Practice

When you subscribe to a hashtag on FediBuzz, the relay records that tag in its filter list. Every public post from a connected instance is scanned. If the post contains the hashtag #Photography, for example, it passes the filter. The relay then forwards that post to your Mastodon server. The post appears in your federated timeline and in the local timeline of your instance if your server settings allow it.

Posts that do not contain any tracked hashtag are never sent to your server. This reduces the amount of irrelevant content your instance must process. It also lowers the risk of spam or off-topic posts appearing in your federated timeline.

Steps to Configure FediBuzz Relay on Your Mastodon Instance

1. Create a FediBuzz Relay account
   Go to the FediBuzz website and sign up. Choose a plan that fits your needs. After registration, you receive a unique relay URL. Copy this URL because you will need it in the next step.
2. Log in to your Mastodon admin panel
   Open your Mastodon instance in a web browser. Click Preferences in the bottom-left menu. Then select Administration from the left sidebar. Click Relays in the submenu.
3. Add the FediBuzz Relay URL
   On the Relays page, click the Add new relay button. Paste the relay URL you copied from FediBuzz into the text field. Click Add relay. Your instance sends a subscription request to FediBuzz.
4. Approve the relay connection
   FediBuzz sends a confirmation request back to your instance. In the Relays page, look for the new relay entry. Click the Enable button next to it. The relay status changes to Enabled. Your instance now accepts filtered posts from FediBuzz.
5. Choose hashtags to follow on FediBuzz
   Return to the FediBuzz website and log in. Navigate to the Subscriptions section. Enter the hashtags you want to track. For example, enter Photography, Linux, or Bookstodon. Save your changes. The relay begins filtering posts with those tags.
6. Verify that posts arrive in your federated timeline
   After a few minutes, check your federated timeline on Mastodon. You should see public posts containing the hashtags you selected. If no posts appear, ensure that other instances connected to the relay are posting with those tags.

Common Mistakes, Limitations, and Things to Avoid

Relay Shows as Pending and Never Enables

This happens when your instance cannot reach the FediBuzz relay server. Check that your Mastodon server can make outbound HTTPS connections. If you run a firewall, allow traffic to the FediBuzz domain on port 443. Also verify that the relay URL is correct. A typo in the URL prevents the handshake from completing.

No Posts Appear Even After Adding Hashtags

Several factors cause this. First, the hashtag you selected might not be in active use on other instances connected to the relay. Second, your instance might have a low federation limit. Mastodon instances can limit the number of relay posts they accept per minute. Check your server logs for relay-related errors. Adjust the relay_follow_limit setting in your Mastodon environment file if needed.

Too Many Irrelevant Posts Still Arrive

FediBuzz Relay filters by hashtag, but a post can include multiple hashtags. If a post contains #Photography and #Cats, it passes the filter even if you only track #Photography. To reduce noise, use more specific hashtags. Instead of #Tech, try #LinuxAdmin or #Python. You can also combine multiple relays with different hashtag sets to separate topics.

Relay Disconnects After Server Restart

Some Mastodon versions lose relay connections after a restart. After restarting your instance, check the Relays page. If the relay shows as Disabled, click Enable again. To automate this, add a cron job that checks relay status every hour. The Mastodon API provides an endpoint to verify relay connectivity.

Item	Standard Mastodon Relay	FediBuzz Topic Relay
Filtering method	No filtering – all public posts forwarded	Hashtag-based filtering before forwarding
Server load impact	High – stores and processes all content	Lower – only relevant posts are stored
Setup complexity	Simple – add URL and enable	Requires FediBuzz account and hashtag selection
Control over content	None – admin cannot choose topics	Full – admin picks specific hashtags
Cost	Free (operated by instance admins)	Free tier with limited hashtags; paid plans for more

After setting up FediBuzz Relay, your instance receives only the public posts that match your chosen topics. Check the relay status weekly to ensure it remains enabled. Adjust your hashtag list as your interests change. For advanced control, consider running your own relay server with custom filtering rules using the Mastodon relay API.