The fediverse is made by and for the people who use it. This is a not-comprehensive and lightly opinionated list of actively maintained, multi-user ActivityPub/fediverse software, and you can help.
Microblogs, mostly excluding forks of more active projects
| Project | Language | Repo | In development since |
|---|---|---|---|
| Letterbook | C# | https://github.com/Letterbook/Letterbook | June, 2023 |
| Emissary | Golang | https://github.com/EmissarySocial/emissary | April, 2020? |
| GoToSocial | Golang | https://github.com/superseriousbusiness/gotosocial | February, 2021 |
| Misskey | Typescript | https://github.com/misskey-dev/misskey | December, 2016 |
| Bonfire | Elixir | https://github.com/bonfire-networks/bonfire-app | February, 2021? |
| Akkoma | Elixir | https://akkoma.dev/AkkomaGang/akkoma | January, 2017? |
| IceShrimp | C# | https://iceshrimp.dev/iceshrimp/Iceshrimp.NET | December, 2023 |
| Ocelot-Social | Typescript | https://github.com/Ocelot-Social-Community/Ocelot-Social | November, 2017 |
Forums, link aggregators, bulletin boards, and similar topic-oriented projects
| Project | Language | Repo | In development since |
|---|---|---|---|
| NodeBB | Javascript | https://github.com/NodeBB/NodeBB | |
| Discourse (plugin) | Ruby | https://github.com/discourse/discourse-activity-pub | |
| Lemmy | Rust | https://github.com/LemmyNet/lemmy | February, 2019 |
| MBin | PHP | https://github.com/MbinOrg/mbin | |
| Piefed | Python | https://codeberg.org/rimu/pyfedi |
Long form blogging platforms
| Project | Language | Repo |
|---|---|---|
| Write Freely | Golang | https://github.com/writefreely/writefreely |
| Wordpress (plugin) | PHP | https://github.com/automattic/wordpress-activitypub |
Media-oriented projects, like photo blogs, image boards, podcasting, or streaming video
| Project | Language | Repo |
|---|---|---|
| Pixelfed | PHP | https://github.com/pixelfed/pixelfed |
| Owncast | Golang | https://github.com/owncast/owncast |
| Peertube | Typescript | https://github.com/Chocobozzz/PeerTube |
| Castopod | PHP | https://code.castopod.org/adaures/castopod |
Generic servers, libraries, and other reusable resources which aren't actually apps
| Project | Language | Repo | In development since |
|---|---|---|---|
| ActivityPubSharp | C# | https://github.com/warriordog/ActivityPubSharp | November, 2022 |
| go-ap | Golang | https://github.com/go-ap | September, 2017 |
| Fedify | Typescript | https://github.com/dahlia/fedify | February, 2024 |
I did a little bit of code archeology to find when some of these projects began development. Anyone who know more about it, feel free to fill in the gaps