How to Choose a Mastodon Relay That Matches Your Topic

If you run a Mastodon server for a specific interest, you may notice the federated timeline shows mostly unrelated content. A Mastodon relay is a server that forwards public posts from one instance to another, helping you fill your local timeline with posts about your chosen topic. This article explains how relays work, what to look for when selecting one, and how to configure your instance to join a topic-specific relay. You will learn how to find, test, and manage relays so your users see more relevant content.

How Mastodon Relays Work and Why Topic Matters

A Mastodon relay is a dedicated server that collects public posts from all subscribed instances and redistributes them. When your instance joins a relay, it sends all public posts from your users to the relay. The relay then forwards those posts to every other instance in the relay network. This process increases the volume of content your local users see in the federated timeline.

The problem arises when you join a general relay. A general relay accepts any instance regardless of topic. Your timeline fills with posts about politics, memes, technology, art, and personal updates. Users interested in a specific niche, such as vintage photography or open source hardware, will see mostly irrelevant posts. A topic-specific relay solves this by restricting membership to instances that focus on a shared subject.

Topic-specific relays are often maintained by community volunteers. They publish a relay URL and a list of allowed topics. Some relays require an application or approval process. Others are open to any instance that declares a specific hashtag as its primary interest. The relay software, typically Mastodon Relay or Pub-Relay, checks the instance description or domain before granting access.

How a Relay Differs from Following Accounts

Following individual accounts manually pulls posts from those users into your home timeline. A relay pulls public posts from every user on every subscribed instance. The relay does not require your users to follow anyone. It fills the federated timeline with a broad stream of topic-related content. This is useful for discovery but can also introduce noise if the relay is too large or includes off-topic instances.

Steps to Find and Join a Topic-Specific Relay

Before you begin, confirm you have admin access to your Mastodon instance. Only administrators can add or remove relays. You will also need the exact relay URL, which typically ends in /inbox or /actor.

1. Browse the relay directory
   Open relaylist.com in your browser. The site lists public relays by category. Look for a relay whose name or description matches your instance topic. For example, fedi.video for video content or mastodon.art for visual art.
2. Check the relay topic and rules
   Click the relay name to view its details. The page shows the relay description, allowed topics, and any membership requirements. Some relays require your instance to have a certain number of users or to use a specific language. Skip relays that do not mention a topic or that accept all instances.
3. Copy the relay URL
   On the relay details page, find the relay address. It looks like https://relay.example.com/inbox. Copy the full URL to your clipboard.
4. Add the relay to your instance
   Log in to your Mastodon admin account. Go to Preferences > Administration > Relays. Click the Add new relay button. Paste the relay URL into the field. Click Submit. The relay will appear in the list with a status of Pending.
5. Wait for approval and verify connection
   Some relays approve automatically. Others require manual review by the relay operator. Check the relay status after a few hours. If the status changes to Enabled, the relay is active. If it remains Pending, contact the relay operator through the contact information on relaylist.com.
6. Monitor the federated timeline
   After the relay is enabled, watch your instance federated timeline for 24 to 48 hours. You should see an increase in posts related to the relay topic. If you see off-topic content, consider removing the relay and trying a different one.

Testing a Relay Before Full Adoption

If you are unsure about a relay, create a test account on a separate small instance or use a staging instance. Add the relay to the test instance and observe the content for a few days. This avoids disrupting your main instance timeline with unwanted posts.

Common Mistakes and Limitations When Choosing a Relay

Joining a relay that does not match your instance language

Many relays are dominated by a single language. If your instance uses Japanese and you join a relay where 90 percent of posts are in English, your users will see content they cannot read. Check the relay description for language tags. If none are listed, search the relay name on social media to see what language the community uses.

Overloading your instance with too many relays

Each relay adds processing load to your server. Public posts from every subscribed instance must be stored, indexed, and delivered to your users. Adding three or more large relays can slow down your instance, increase database size, and raise bandwidth costs. Start with one relay and add a second only if the first does not provide enough relevant content.

Ignoring the relay blocklist feature

Even a topic-specific relay may include instances that post spam, hate speech, or illegal content. Mastodon allows you to block specific domains from reaching your instance even if they are part of the same relay. Go to Preferences > Administration > Domain Blocks. Add the domain you want to block. This prevents posts from that domain from appearing in your federated timeline without removing the relay entirely.

Assuming the relay will stay on topic

Relay operators can change the rules or allow new instances at any time. A relay that was focused on photography in 2024 might accept general instances in 2025. Revisit your relay list every few months. Remove relays whose content no longer matches your topic.

Mastodon Relay vs Pub-Relay: Feature Comparison

Item	Mastodon Relay	Pub-Relay
Software type	Official Mastodon relay packaged as a separate app	Community-developed relay written in Go
Setup complexity	Requires Ruby and Mastodon environment	Single binary, easier to deploy
Topic filtering	No built-in topic filter; relies on instance approval	Supports hashtag-based filtering and allowlists
Performance on large networks	Can slow down with hundreds of instances	Designed for high throughput and low latency
Community adoption	Widely used on older instances	Gaining popularity for topic-specific relays

This comparison helps you understand the relay software behind a given relay URL. If you plan to run your own relay, Pub-Relay offers better topic control. If you only join relays, the software matters less than the operator moderation policy.

Now you can evaluate relay options based on topic, language, and software. Start by visiting relaylist.com and filtering by your interest area. Add one relay at a time and monitor the federated timeline for relevance. Use the domain block feature to remove unwanted sources without leaving the relay. If you run a large instance, consider setting up your own Pub-Relay to control exactly which instances participate.