Mastodon
publishedDecentralized social networking via ActivityPub
An open-source, federated social network. No ads, no tracking, no algorithmic feed by default. Users choose their server (instance), each with its own moderation policies. Supports account migration between instances.
Trust Surface
Interoperability
UX & Feed
Governance
Business Model
Quick Facts
| RSS | Supported |
| Federation | yes |
| API | Available |
| Chronological Feed | yes |
| Algorithmic Feed | optional |
| Deletion | yes |
| Open Source | yes |
| Moderation Transparency | public |
Why It Belongs
Why It Belongs Here
Mastodon is the most widely adopted ActivityPub implementation. It demonstrates that social networking can work without surveillance capitalism.
Key strengths: chronological timeline by default, full account portability between instances, comprehensive API, and transparent moderation policies per instance. The federated model means no single entity controls the network.
Tradeoffs
Tradeoffs
- Federation means public data: Posts federate to other servers, reducing privacy control over distribution
- Instance fragmentation: The instance model creates discovery and onboarding friction
- Moderation variance: Quality of moderation depends entirely on instance administrators
- Content discoverability: Harder to find content compared to centralized platforms
- Complexity for new users: The instance concept is confusing for people used to centralized platforms
- Resource-heavy self-hosting: Running an instance requires significant server resources
Claims (5)
No algorithmic engagement optimization — chronological timeline by default.
Full account portability between instances via ActivityPub migration.
Federation means posts may be distributed beyond the user's chosen instance without explicit consent.
Instance moderation quality varies dramatically — there is no baseline guarantee.
Self-hosting requires significant resources: 2+ vCPU, 4GB+ RAM, PostgreSQL, Redis, Elasticsearch.
Evidence (6)
Fedi.Tips: Mastodon does not use algorithms — chronological timeline confirmed
strongHome timeline displays posts in strict chronological order. No algorithmic reordering, no interaction tracking to influence content, no promoted content. "Trending Posts" uses simple most-boosted metric, not opaque recommendation algorithms.
Mastodon official docs: account migration transfers followers only, not posts
strongMigration automatically transfers followers only. Does NOT transfer follows, blocks, mutes, bookmarks, or lists (must export/import CSV manually). Posts and media CANNOT be transferred: "Mastodon currently does not support importing posts or media." 30-day cooldown between migrations.
EFF: "Is Mastodon Private and Secure? Let's Take a Look"
strongEFF analysis: "your posts and direct messages are accessible by those running the services." DMs are NOT end-to-end encrypted. Mastodon warns: "Posts on Mastodon are not end-to-end encrypted. Do not share any sensitive information." Data deletion across federated instances is technically difficult.
Privacy Guides: Mastodon privacy and security analysis (2025)
strongPrivacy Guides warned: "If you send a private mention post to someone on a different instance, this person's instance administration team will now have access to your message." Federation is an interoperability technology, not a privacy technology.
Internet Policy Review: content moderation challenges vary by instance characteristics
strongPeer-reviewed article: "challenges and responses vary depending on instance characteristics: size, thematic focus and geography." Multiple instances shut down in 2024-2025 (moth.social, botsin.space). Most instances run by volunteers with limited resources.
Mastodon server requirements: 4 vCPU, 8-16 GB RAM for small communities
moderateCommunity guide recommends for 100-500 active users: 4 vCPU, 8-16 GB RAM, 200 GB NVMe SSD. Single Mastodon worker needs 2-3 GB RAM, plus ~1 GB for Sidekiq. Official docs specify Linux VPS with root access but give no specific hardware numbers.