How to Protect Your Privacy on Mastodon

Mastodon has become one of the most popular alternatives to centralized social networks, offering a decentralized, ad-free experience powered by the fediverse. But decentralization does not automatically equal privacy. Mastodon's federated architecture introduces unique risks that most users never consider. Here is how to take control of your privacy on Mastodon and the broader fediverse.

How Mastodon's Federated Architecture Affects Your Privacy

Unlike centralized platforms such as X or Instagram, Mastodon is not a single service run by one company. It is a network of thousands of independently operated servers, called instances, that communicate with each other using the ActivityPub protocol. When you create a Mastodon account, you are trusting the administrator of your chosen instance with your data.

This architecture has real privacy implications. When you post on Mastodon, your content does not stay on your home instance alone. Through federation, your posts are transmitted to every instance that houses at least one of your followers. If someone boosts your post, it spreads further — potentially reaching thousands of additional servers. Each of those servers stores a copy of your content, and you have no control over how those copies are handled, stored, or deleted.

Choosing a Privacy-Focused Instance

Your choice of instance is the single most important privacy decision you will make on Mastodon. Your instance administrator has access to your email address, IP address logs, and — because Mastodon direct messages are not end-to-end encrypted — even the content of your private messages.

Here is what to look for when evaluating an instance:

• Read the privacy policy and terms of service. Not all instances publish these documents. Avoid instances that lack clear data handling policies.
• Check who runs the instance. Is it a registered organization, a community group, or a single anonymous individual? Established organizations with transparent leadership are generally safer bets.
• Look for a clear moderation policy. Good moderation protects you from harassment and spam, both of which can compromise your privacy.
• Check the instance's jurisdiction. Data protection laws vary by country. An instance based in the EU, for example, is subject to GDPR, which gives you stronger rights over your data.
• Use curated directories. Resources like Fedi.garden maintain lists of well-run instances that meet minimum standards for reliability and responsible moderation.

Essential Mastodon Privacy Settings

1. Lock Your Account

By default, anyone can follow you on Mastodon. Locking your account requires you to manually approve follow requests, which prevents strangers from accessing your followers-only posts.

1. Go to Preferences > Profile
2. Enable "Require follow requests"

2. Set Your Default Post Visibility

Mastodon offers four post visibility levels that you should understand and use deliberately:

• Public: Visible to everyone, appears on public timelines and search results
• Unlisted (Quiet Public): Visible to anyone who visits your profile, but does not appear on public timelines or in search results
• Followers-only: Only your approved followers can see the post in their home feeds
• Mentioned people only: Only users you mention in the post can see it (similar to a direct message)

Consider setting your default visibility to Unlisted or Followers-only to reduce your exposure on public timelines. You can always choose to make individual posts public when appropriate.

3. Hide Your Social Graph

Your follower and following lists can reveal a lot about you — your interests, your community, and your connections. Mastodon lets you hide these lists:

1. Go to Preferences > Profile
2. Enable "Hide your social graph"

This makes your following and follower counts visible, but the actual lists private to you only.

4. Enable Two-Factor Authentication

Protect your account from unauthorized access:

1. Go to Preferences > Account > Two-factor Auth
2. Set up authentication using a TOTP app or a hardware security key
3. Save your recovery codes in a secure password manager

5. Use the Auto-Delete Feature

Mastodon supports automatic deletion of old posts after a specified period. This is a powerful privacy tool that limits the amount of historical data available about you:

1. Go to Preferences > Automated post deletion
2. Enable it and set your preferred retention period

Keep in mind that auto-delete only removes posts from your home instance. Copies on remote instances may persist.

6. Configure Search and Indexing

Mastodon allows you to opt out of search engine indexing and full-text search discovery:

1. Go to Preferences > Profile
2. Disable "Suggest profile to others" and "Include public posts in search results"

Direct Messages Are Not Private

This is one of the most misunderstood aspects of Mastodon privacy. The "mentioned people only" visibility level functions like a direct message, but these messages are not end-to-end encrypted. The administrators of both the sender's and recipient's instances can potentially read their contents.

Profile and Posting Best Practices

Beyond settings, how you use Mastodon matters just as much for your privacy:

• Minimize personal details in your bio. Avoid listing your employer, school, city, or full name unless you want that information to be permanently public and federated across thousands of servers.
• Use a pseudonym if anonymity matters to you. There is no requirement to use your real name on Mastodon.
• Use a dedicated email address for your Mastodon account that is not tied to your real identity.
• Be cautious with images. Photos can contain EXIF metadata including GPS coordinates. While Mastodon strips EXIF data on upload, third-party clients and scrapers may not.
• Review authorized applications regularly. Revoke access to third-party apps you no longer use via Preferences > Account > Authorized apps.
• Use a VPN to mask your IP address from your instance administrator and any instances your traffic passes through.

How Mastodon Compares to Centralized Platforms

Mastodon offers meaningful privacy advantages over platforms like X, Facebook, and Instagram:

• No targeted advertising. Mastodon does not collect behavioral data to sell ads. There is no advertising infrastructure at all.
• No algorithmic surveillance. There are no recommendation algorithms tracking your behavior to optimize engagement.
• Data portability. You can export your data and migrate your account to a different instance, taking your followers with you.
• Transparent, open-source code. Anyone can audit Mastodon's source code to verify its privacy claims.

However, Mastodon also has privacy trade-offs that centralized platforms do not:

• Trust is distributed, not eliminated. Instead of trusting one large corporation, you are trusting potentially dozens of volunteer instance administrators.
• Inconsistent data handling. Each instance has its own policies, and many lack formal privacy policies entirely.
• Limited deletion guarantees. Federated content is much harder to fully delete than content on a centralized platform.

Protect Your Privacy Beyond Mastodon

Even with perfect Mastodon settings, your privacy is only as strong as your overall digital footprint. Data brokers and people-search websites can link your Mastodon handle to your real identity, home address, phone number, and other personal details — especially if you use the same email address or username across multiple platforms.

A comprehensive approach to privacy should include:

• Removing your personal information from data broker sites — PrivacyOn continuously monitors and removes your data from 200+ data broker and people-search sites, keeping your personal information from being connected back to your online profiles
• Using unique usernames and email addresses across different platforms to prevent cross-referencing
• Regularly searching for yourself online to identify new exposures before others find them

Mastodon Privacy Checklist

Use this quick reference to harden your Mastodon privacy:

1. Choose an instance with a clear privacy policy and trustworthy administration
2. Lock your account to require follow approval
3. Set default post visibility to Unlisted or Followers-only
4. Hide your social graph
5. Enable two-factor authentication
6. Turn on automatic post deletion
7. Opt out of search engine indexing and discovery
8. Never share sensitive information via Mastodon DMs
9. Minimize personal details in your profile
10. Use a dedicated email address and a VPN
11. Revoke unused third-party app access
12. Remove your data from data broker sites with PrivacyOn

Stay in Control

Mastodon's decentralized model puts more power in your hands than any corporate-owned social network — but it also requires you to be more deliberate about your privacy choices. By selecting a trustworthy instance, configuring your settings carefully, and managing your broader digital footprint with tools like PrivacyOn, you can participate in the fediverse without sacrificing your personal privacy.