*Note*: Tools with open protocol issue (not yet implemented), not fully open sourced code, no documentation at all, or alpha state with development inactive for several months, not added for now.
*Note*: Most of these projects include both a back-end and a web client, but this list can also include projects that are only a back-end. Projects that are only a web app, for use with an existing back-end, will go on the [client watchlist ](https://git.feneas.org/feneas/fediverse/wikis/watchlist-for-client-apps).
* :heavy_check_mark: [Aardwolf](https://github.com/Aardwolf-Social/aardwolf) - aims to create a FB-a-like in Rust. Still in alpha, Web demo promised soon.
* :tada: :heavy_check_mark: [Epicyon](https://code.freedombone.net/bashrc/epicyon) - AP server created for use on low-powered hardware, by Freedombone developers
* :tada: :heavy_check_mark: [Friendica](https://friendi.ca/) - [AP support was rolled out in the 2019.01 release](https://friendi.ca/2019/01/21/friendica-2019-01-released/).
* :heavy_check_mark: [GNU social](https://git.gnu.io/gnu/gnu-social/issues/256) - AP support was done as a Summer of Code project, but not yet merged into mainline.
* :tada: :heavy_check_mark: [Honk](https://humungus.tedunangst.com/r/honk) by [@tedu](https://honk.tedunangst.com/u/tedu) - Go ActivityPub server focused on minimal setup and support costs
* :tada: :heavy_check_mark: [Kroeg](https://puckipedia.com/kroeg) - [current source repo](https://git.puckipedia.com/kroeg) seems active - [older GH repo](https://github.com/jfmcbrayer/Kroeg) with no activity for 2 years).
* :tada: :heavy_check_mark: [microblog.pub](https://github.com/tsileo/microblog.pub) - single-user microblog server, "Getting closer to a stable release, it should be the "last" migration". Like Pubgate, uses [little-boxes AP library](https://github.com/tsileo/little-boxes)
* :heavy_check_mark: [microstatus](https://github.com/Arkanosis/microstatus) - Lightweight Mastodon- and GNU Social-compatible ActivityPub and OStatus server implementation, "still under active design and not yet ready for mainstream usage".
* :tada: :black_nib: [Smithereen](https://pinafore.social/statuses/103081791846631680) - "VKontakte-like social network written in Java ... with friends and walls and photos and groups... Of which currently only friends and walls are implemented. Not quite ready enough and so not published anywhere yet, but I'm looking forward to it."
* :tada: :heavy_check_mark: [SocialHome](https://git.feneas.org/socialhome/socialhome/issues/522) - currently working on adding AP support to their [Python federation library](https://git.feneas.org/jaywink/federation/issues/7)
* :tada: :black_nib: [Zap](https://zotlabs.org/page/zap/zap) - [Zot app](https://git.feneas.org/feneas/fediverse/wikis/watchlist-for-Zot-apps) that supports AP natively since the 2019-09-22 release
* :black_nib: [Diffu](https://mockup.diffu.social/) - an attempt at a federated Tumblr/ Medium, aimed at hosting long form articles that easily and neatly embed other kinds of content from any fediverse platform (microblog posts, PixelFed images, PeerTube videos etc). Proposed by a French company called Befox, who attempted to crowdfund development (inspired perhaps by the success or PeerTube and Mobilizon), but didn't hit their target.
* :heavy_check_mark: [Huzbilla](https://project.hubzilla.org/) - federated CMS with a range of groupware tools available as plug-ins. Support AP with the [pubcrawl plug-in](https://framagit.org/hubzilla/addons/tree/master/pubcrawl).
* :heavy_check_mark: [WordPress](https://gitlab.com/fediverse/fediverse.gitlab.io/wikis/Wordpress-integration-with-Fediverse) - an [AP plug-in](https://wordpress.org/plugins/activitypub/) by @pfefferle@mastodon.social, that allows users on AP apps to follow WP blogs, was recently updated. See also [Pterotype](https://getpterotype.com/), which @pfefferle says is currently more feature complete. WordPress is now [listed as a project on the-federation.info](https://the-federation.info/wordpress).
* [Anancus](https://gitlab.com/tuxether/anancus) - by [@tuxether](https://floss.social/@tuxether), [discontinued](https://gitlab.com/tuxether/anancus/issues/2)?
* :black_nib: [Flarum](https://github.com/squeevee/flarum-ext-feddle) - experimental plugin for the [Flarum](https://flarum.org/) forum software by [@squeevee](https://yiff.life/@squeevee/102496777538790361)
* :heavy_check_mark: [Guppe](https://github.com/wmurphyrd/guppe) by [@datatitian](https://social.coop/@datatitian/102837577105371476) - adds "groups" support as group-type actors
* :heavy_check_mark: [Lemmy](https://github.com/dessalines/lemmy) by [@LemmyDev](https://mastodon.social/@LemmyDev/102106696961226378)
* :heavy_check_mark: [Prismo](https://gitlab.com/mbajur/prismo) contact at [@prismo](https://mastodon.social/@prismo)
* :black_nib: [Smilodon](https://source.puri.sm/liberty/host/smilodon/) - the server by Purism used in LibreOne, not the abandoned Tuxcraft server or Pylodon client. "A complementary fork of Mastodon, focusing on opt-in public spaces."
* :black_nib: [Marmota](https://gitlab.com/Nefix/marmota/issues?label_name=ActivityPub) - service like Spotify or any music streaming service, initial commit;
Friendica (see above) has an events engine but there are conflicting reports about whether or not federation of events over AP is working yet. [NextCloud federated events](https://github.com/nextcloud/calendar/pull/878) are in the works but this may or may not be AP-compatible.
* [MoodleNet](https://gitlab.com/moodlenet) - a [social client for Moodle](https://moodle.com/moodlenet) LMS (Learning Management System) aimed at helping teachers collaboratively collate and curate sets of OER (Open Educational Resources).
* :black_nib: [ActivityPubMock](https://gitlab.com/evanp/activitypub-mock) - "If you are implementing an AP server or an AP client, you can use this mock in your unit tests to check that it's behaving correctly"
* :black_nib: [ActivityPHP](https://landrok.github.io/activitypub/) - library for AP in PHP by [@landrok](https://cybre.space/@landrok)
* :heavy_check_mark: [BridgyFed](https://github.com/snarfed/bridgy-fed/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+activitypub) - bridge to the IndieWeb
* :heavy_check_mark: [CommonsPub](https://gitlab.com/OpenCoop/CommonsPub) - a fork of Pleroma intended to provide a UX that supports economic transactions and coordination
* :black_nib: [astreams](https://github.com/MatejLach/astreams) - "ActivityStreams 2.0 encoding/decoding for Go" developed by @MatejLach@social.matej-lach.me for use with [fediQuest](https://shapegoal.org/)
* :heavy_check_mark: [ForgeFed](https://notabug.org/peers/forgefed) (formerly GitPub) - a set of extensions to AP for federation between code forges (Git hosting sites like GitLab, Gogs, Gitea etc) by [@forgefed](https://floss.social/@forgefed)
* [Indienet](https://source.ind.ie/indienet) - [homepage](https://indienet.info/) - projects goals seem similar to the federated homepages of the IndieWeb, but federated using AP.
* :heavy_check_mark: [Nautilus](https://github.com/aaronpk/Nautilus) - a tool to allow self-hosted blog sites to have their posts followed and commented on via AP
* :heavy_check_mark: [pubgate](https://github.com/autogestion/pubgate) - "Asyncronous Lightweight ActivityPub API ... Based on little-boxes. Implements both the client-to-server API and the federated server-to-server API. Compatible with Mastodon, Pleroma and microblog.pub"
Projects that are officially abandoned by the maintainers or with no signs of life on their code repo or any other official channels for more than a year. Listed on this watchlist just in case anyone doesn't realize they're dead, and thinks we just didn't know about them. Also in case a project is orphaned, then reactivated by a new developer.
* [ActivityPub.jl](https://github.com/Matt5sean3/ActivityPub.jl) - AP support in the Julia language by [@Matt5sean3](https://rva.party/@Matt5sean3), no commits since August, 2018. Project is [missing, presumed dead](https://github.com/Matt5sean3/ActivityPub.jl/issues/1).
* [Calendar-social](https://gitea.polonkai.eu/gergely/calendar-social/) - was definitely planning to [implement AP](https://gitea.polonkai.eu/gergely/calendar-social/issues/122). Missing, [presumed discontinued](https://gitea.polonkai.eu/gergely/calendar-social/issues/123)
* [CloutStream](https://web.archive.org/web/20180808152307/http://cloutstream.com/) - proposed by [@mwpdx](https://mstdn.io/@mwpdx/100591379202470027) as a federated replacement for LinkedIn. Both @cloutstream and @mwpdx Mastodon.social accounts appears to have been removed from the server, all the project tools appear to be down, or removed from the host.
* [Fontina](https://github.com/beta-phenylethylamine/fontina) - proposed as a photo-sharing social media network. GH repo has gone read-only, and now says "dead project".
* :tada: :heavy_check_mark: [GangGo](https://git.feneas.org/ganggo/federation/issues/17) - Seems to have settled on using [Go-Fed for AP federation](https://git.feneas.org/ganggo/activity). Developer has suspended development for the foreseeable future.
* [MediaGoblin](https://issues.mediagoblin.org/ticket/5503) - streaming of any and all media files. Currently in "[unofficial retirement](https://news.ycombinator.com/item?id=19779594)".
* [Numa](https://github.com/numaverse/numaverse-gateway/issues/3) - built on Ethereum blockchain but intended to federate with AP. No commits since April 2018. No reply on issue about AP compatibility testing from May 8. Homepage now a spam site.
* [Osada](https://framagit.org/zot/osada) - Osada was a full featured social network application running under the ActivityPub protocol. It also communicated with and inter-operated with servers on the Zot6 network. Abandoned by the developers in March 2019.
* [Pylodon](https://github.com/rowanlupton/pylodon) - Flask-based (Python) ActivityPub server , [source code also on GitLab](https://gitlab.com/rowanlupton/pylodon), no updates on either repo for about a year, nor on their [Smilodon client app](https://github.com/rowanlupton/smilodon).
* [Quit.im](https://quit.im) - this was a photo-sharing web client for a GNU social server, rather than a completely separate app. It would become an AP implementation when the AP plug-in for GS is done, but it's been obsoleted by the release of PixelFed.
* [Smilodon](https://gitlab.com/tuxcrafting/smilodon) (server by Tuxcraft) - abandoned by developer "I'm now [working on Sminos](https://gitlab.com/tuxcrafting/sminos/issues/1) and so this will probably be 100% abandoned. There's not much to salvage, its code is cancer." Sminos appears to have never got beyond the initial commits.
Aside from project homepages and issue trackers, and comments made on the fediverse, the [SocialWG has a list](https://www.w3.org/wiki/Socialwg/ActivityPub_network) of projects they hoped would implement ActivityPub and links to Issues where it's discussed. Also, there is an [implementation report on ActivityPub.rocks](https://activitypub.rocks/implementation-report/). @Mayel from Social.coop created a [web spreadsheet of AP apps](https://ethercalc.org/fediverse-stacks) and their characteristics. More projects using AP are [profiled on We Distribute](http://wedistribute.org/) by Sean Tilley and his team. [Alternative.to](https://alternativeto.net/list/5696/activitypub) has a list of AP servers and client apps. The [ActivityPub tag on GH](https://github.com/topics/activitypub) is also a way to discover projects experimenting with AP.
