Mastodon

Mastodon provides a self‑hosted platform for microblogging that can federate with other instances, forming a globally interconnected network of users. It implements the ActivityPub protocol, allowing posts, follows, and interactions to be shared across independent servers while preserving a unified timeline for participants. The software is open source and available under a free tier, enabling individuals or organizations to deploy their own instance without licensing costs.

The system targets communities that want to maintain control over their data and moderation policies while still participating in a larger social ecosystem. By running their own server, administrators can customize rules, branding, and technical settings to fit specific group needs, yet remain compatible with the broader federation of Mastodon instances.

Key characteristics include stable, mature code that has been maintained for several years, and a focus on privacy and decentralization. The original server is operated by Mastodon GmbH for the common good, reflecting the project’s commitment to a community‑driven, open‑source communication service.