Note

Want to learn more about Mastodon? Click below to find out more in a video.

Mastodon is a free, open-source social network server based on ActivityPub where users can follow friends and discover new ones. On Mastodon, users can publish anything they want: links, pictures, text, and video. All Mastodon servers are interoperable as a federated network (users on one server can seamlessly communicate with users from another one, including non-Mastodon software that implements ActivityPub!)

Navigation

• Project homepage 🐘
• Donate to support development 🎁
  • View sponsors
• Blog 📰
• Documentation 📚
• Official container image 🚢

Features

Part of the Fediverse. Based on open standards, with no vendor lock-in. - the network goes beyond just Mastodon; anything that implements ActivityPub is part of a broader social network known as the Fediverse. You can follow and interact with users on other servers (including those running different software), and they can follow you back.

Real-time, chronological timeline updates - updates of people you're following appear in real-time in the UI.

Media attachments - upload and view images and videos attached to the updates. Videos with no audio track are treated like animated GIFs; normal videos loop continuously.

Safety and moderation tools - Mastodon includes private posts, locked accounts, phrase filtering, muting, blocking, and many other features, along with a reporting and moderation system.

OAuth2 and a straightforward REST API - Mastodon acts as an OAuth2 provider, and third party apps can use the REST and Streaming APIs. This results in a rich app ecosystem with a variety of choices!

Deployment

Tech stack

• Ruby on Rails powers the REST API and other web pages.
• PostgreSQL is the main database.
• Redis and Sidekiq are used for caching and queueing.
• Node.js powers the streaming API.
• React.js and Redux are used for the dynamic parts of the interface.
• BrowserStack supports testing on real devices and browsers. (This project is tested with BrowserStack)
• Chromatic provides visual regression testing. (This project is tested with Chromatic)

Requirements

• Ruby 3.3+
• PostgreSQL 14+
• Redis 7.0+
• Node.js 22+
• FFmpeg 5.1+

This repository includes deployment configurations for Docker and docker-compose, as well as for other environments like Heroku and Scalingo. For Helm charts, reference the mastodon/chart repository. A standalone installation guide is available in the main documentation.

Contributing

Mastodon is free, open-source software licensed under AGPLv3. We welcome contributions and help from anyone who wants to improve the project.

You should read the overall CONTRIBUTING guide, which covers our development processes.

You should also read and understand the CODE OF CONDUCT that enables us to maintain a welcoming and inclusive community. Collaboration begins with mutual respect and understanding.

You can learn about setting up a development environment in the DEVELOPMENT documentation.

If you would like to help with translations 🌐 you can do so on Crowdin.

LICENSE

Copyright (c) 2016-2026 Eugen Rochko (+ mastodon authors)

Licensed under GNU Affero General Public License as stated in the LICENSE:

Copyright (c) 2016-2026 Eugen Rochko & other Mastodon contributors

This program is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option) any
later version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
details.

You should have received a copy of the GNU Affero General Public License along
with this program. If not, see https://www.gnu.org/licenses/