What is Mastodon used for?

Mastodon is a free, open-source social network server built on ActivityPub, where independent servers federate into the wider Fediverse. It is a good fit for running a community microblogging server, organization-owned social presence and joining the Fediverse.

Is Mastodon open source?

Yes. Mastodon is open source under the AGPL-3.0 licence. Its source code is on GitHub at mastodon/mastodon and is written mainly in Ruby.

Yes. Mastodon is open source, so the software itself is free to use. A managed cloud version is also available.

Can I self-host Mastodon?

Yes. Mastodon can be self-hosted on your own server or infrastructure.

What is Mastodon an alternative to?

Mastodon is an open-source alternative to X (Twitter), Threads, Weibo and VK. Other open-source alternatives to X (Twitter) include Misskey, Bluesky and Elk.

Is Mastodon actively maintained?

Yes. The most recent commit to Mastodon was on 2 October 2026, and the latest release is v4.7.3, published on 1 October 2026. The project has 50k stars on GitHub.

Mastodon: open-source alternative to X (Twitter), Threads

About Mastodon

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

Good fit for

→Running a community microblogging server
→Organization-owned social presence
→Joining the Fediverse

Built with: Ruby; Docker
Tags: microblogging; fediverse; activitypub; social-network; self-hosted; ruby; federation; community

Mastodon: questions and answers

What is Mastodon used for?: Mastodon is a free, open-source social network server built on ActivityPub, where independent servers federate into the wider Fediverse. It is a good fit for running a community microblogging server, organization-owned social presence and joining the Fediverse.
Is Mastodon open source?: Yes. Mastodon is open source under the AGPL-3.0 licence. Its source code is on GitHub at mastodon/mastodon and is written mainly in Ruby.
Is Mastodon free?: Yes. Mastodon is open source, so the software itself is free to use. A managed cloud version is also available.
Can I self-host Mastodon?: Yes. Mastodon can be self-hosted on your own server or infrastructure.
What is Mastodon an alternative to?: Mastodon is an open-source alternative to X (Twitter), Threads, Weibo and VK. Other open-source alternatives to X (Twitter) include Misskey, Bluesky and Elk.
Is Mastodon actively maintained?: Yes. The most recent commit to Mastodon was on 2 October 2026, and the latest release is v4.7.3, published on 1 October 2026. The project has 50k stars on GitHub.