Mastodon is a decentralized, open-source social network built on the ActivityPub protocol. Anyone can run a server; people on one server can follow and talk to people on others. Timelines are chronological by default, and there is no advertising or engagement-ranking business model.
NGI0 Discovery funded groups, advanced filtering, and better moderation tools so instance operators can handle reports in batches and users can talk in smaller circles without leaving the Fediverse. Website: joinmastodon.org.
Mastodon runs on infrastructure communities control—no single canonical host. The live instances below are examples only; deploy your own with the generic docs.
Generic (Mastodon project): docs.joinmastodon.org.
Example instances (live):
| Instance | Notes |
|---|---|
| fosstodon.org | FOSS community instance |
| chaos.social | CCC-adjacent community |
| social.coop | Social.coop community instance |
Microblogging on X / Twitter concentrates public conversation in one corporate feed: ranking, bans, and outages hit everyone at once, and the social graph is a product.
Mastodon splits that graph across independently run servers. Communities choose their own rules and can still reach the rest of the Fediverse. NGI-funded groups and moderation work reduce the excuse that “we cannot run this ourselves.” Users still depend on the instance they pick — same class of trust as an XMPP or mail operator — but they can leave without abandoning the protocol.