Mastodon
A free, open-source social network server built on ActivityPub, where independent servers federate into the wider Fediverse.
- GitHub stars
- 50k
- Last commit
- today
- Latest release
- v4.7.3
- Licence
- AGPL-3.0
- Self-hosted
- Yes
- Hosted version
- Available

Mastodon is a social network server, free and open source, that runs on the ActivityPub standard so users can follow friends and find new accounts. People can publish links, pictures, text and video. Every Mastodon server is interoperable with the others as a federated network, and it can also communicate with other software that implements ActivityPub. It is written in Ruby and released under the AGPL-3.0 license.
Features include real-time, chronological timeline updates, media attachments for images and videos, and safety and moderation tools such as private posts, locked accounts, filters for phrases, muting and blocking, plus reporting and moderation. Mastodon acts as an OAuth2 provider with a REST API and a Streaming API, which has produced a rich ecosystem of third-party apps.
The software belongs to the Fediverse, which is built on open standards and avoids vendor lock-in. The backend uses Ruby on Rails with PostgreSQL, and an official container image is available. You can run your own server or join an existing one, so it suits communities, organizations and individuals who want control over their social platform.
Key features
- ActivityPub federation with other servers
- Real-time chronological timelines
- Image and video attachments
- Moderation, filtering, muting and blocking tools
- OAuth2 provider with REST and Streaming APIs
- Official container image
Pricing: Free and open source under the AGPL-3.0 license.

