* :heavy_check_mark: [**ActivityPhp**](https://github.com/landrok/activitypub) ([site](https://landrok.github.io/activitypub), [Fedi account](https://cybre.space/@landrok)): A PHP implementation of ActivityPub protocol based upon the ActivityStreams 2.0 data format. `MIT, PHP`
* :heavy_check_mark: [**ActivityPub-PHP**](https://github.com/pterotype-project/activitypub-php) ([Fedi account](https://mastodon.technology/@jdormit)): A PHP implementation of the ActivityPub protocol (used in Pterotype plugin). `MIT, PHP`
* :heavy_check_mark: [**activityPub4j**](https://github.com/msummers/activityPub4j): W3C ActivityPub and ActivityStreams implementation in Java using Spring Boot. `?, Java` (no license, see: [issue](https://github.com/msummers/activityPub4j/issues/1))
* :heavy_check_mark: [**ActivityStreams**](https://github.com/OpenSocial/activitystreams): Full ActivityStreams 1.0 and 2.0 reference implementation in Java. `Apache-2.0, Java`
* :heavy_check_mark: [**astreams**](https://github.com/MatejLach/astreams) ([Fedi account](https://social.matej-lach.me/@MatejLach)): A hand-crafted implementation of the Activity Streams 2.0 specification in Go, especially suitable for projects implementing ActivityPub. `AGPL-3.0, Go`
* :heavy_check_mark: [**atoot**](https://github.com/popura-network/atoot): Library providing an easy way to create Mastodon API applications `MIT, Python`
* :heavy_check_mark: [**CommonsPub**](https://gitlab.com/CommonsPub) ([site](http://commonspub.org)): Building blocks for creating multifunctional federated networks with ActivityPub. `AGPL-3.0, Elixir`
* :heavy_check_mark: [**corpus-activity-streams**](https://github.com/ryanatkn/corpus-activity-streams): Activity Streams 2.0 vocabulary data and alternative docs. `Unlicense license, Typescript`
* :heavy_check_mark: [**Express ActivityPub**](https://github.com/dariusk/express-activitypub): A very simple reference implementation of an ActivityPub server using Express.js. `MIT, Javascript`
* :heavy_check_mark: [**Federation**](https://git.feneas.org/jaywink/federation): Library to abstract social web federation protocols like ActivityPub, Diaspora and Matrix (see [docs](https://federation.readthedocs.io)) `BSD-3-clause, Python`
* :heavy_check_mark: [**Golang ActivityPub**](https://github.com/go-ap) ([Fedi account](https://metalhead.club/@mariusor)): Libraries for using ActivityPub in the Go language. `MIT, Go`
* :heavy_check_mark: [**go-fed activity**](https://github.com/go-fed/activity) ([site](https://go-fed.org), [Fedi account](https://mastodon.technology/@cj)): Full ActivityStreams & ActivityPub implementation in Golang. Extensions can be easily added by design-time code generation from JSON-LD schema's (also supports [ForgeFed](https://forgefed.peers.community) this way, by default). `BSD-3-clause, Go`
* :heavy_check_mark: [**go-fed apcore**](https://github.com/go-fed/apcore) ([site](https://go-fed.org), [Fedi account](https://mastodon.technology/@cj)): A powerful single server ActivityPub framework for performant Fediverse applications. `AGPL-3.0, Go`
* :heavy_check_mark: [**Little Boxes**](https://little-boxes.readthedocs.io): Tiny ActivityPub framework, both database and server agnostic `ISC, Python`
* :heavy_check_mark: [**Little Library**](https://github.com/Alamantus/little-library): A digital give-a-book, take-a-book library for ebooks `AGPL-3.0, Javascript`
* :heavy_check_mark: [**Pubstrate**](https://gitlab.com/dustyweb/pubstrate): ActivityStreams and ActivityPub library implementation for GNU Guile. Includes a full ActivityStreams library and most of an ActivityPub implementation. `GPL-3.0, Guile`
* :heavy_check_mark: [**ActivityPub for Drupal**](https://github.com/swentel/activitypub) ([Lead dev](https://realize.be/user/1)): ActivityPub integration for Drupal 8 (see also [lite version](https://www.drupal.org/project/activitypub/) at Drupal) `GPL-2.0, PHP`
* :heavy_check_mark: [**Hugo-ActivityStreams**](https://git.jlel.se/jlelse/hugo-activitystreams): A Hugo module for use in Hugo, to generate ActivityStreams representations of posts. ([mirror](https://codeberg.org/jlelse/hugo-activitystreams)) `MIT, Go`
* :heavy_check_mark: [**Pterotype**](https://github.com/pterotype-project/pterotype): WordPress plugin. Pterotype connects your blog to the Fediverse by giving it an ActivityPub feed `MIT, PHP`
* :heavy_check_mark: [**XWiki Extension for ActivityPub**](https://github.com/xwiki-contrib/application-activitypub) ([site](https://extensions.xwiki.org/xwiki/bin/view/Extension/ActivityPub%20Application/), [Fedi account](https://social.weho.st/@XWiki)): An implementation of the ActivityPub protocol for XWiki (see [forum discussion](https://forum.xwiki.org/t/new-application-activitypub/6186)). `LGPL-2.1, Java`
* :heavy_check_mark: [**Social relay**](https://git.feneas.org/jaywink/social-relay): Public post relay for the diaspora* federated social network protocol. `AGPL-3.0, Python`
* :heavy_check_mark: [**BridgyFed**](https://github.com/snarfed/bridgy-fed) ([site](https://fed.brid.gy)): Bridges the IndieWeb to federated social networks: ActivityPub, OStatus, etc. `Public Domain, Python`
* :heavy_check_mark: [**Fediverse-Action**](https://github.com/rzr/fediverse-action): Github Action that posts to Fediverse when code is changed. `ISC License, Javascript`
* :heavy_check_mark: [**feed2toot**](https://gitlab.com/chaica/feed2toot): Parses RSS feeds, identifies new posts and posts them on the Mastodon social network ([using the Mastodon API]((https://gitlab.com/chaica/feed2toot/issues/35#note_289027030))). `MIT, Python`
* :heavy_check_mark: [**gemifedi**](https://git.sr.ht/~boringcactus/gemifedi): A Gemini frontend to the fediverse (specifically, Mastodon and Pleroma instances). `AGPL-3.0, Rust`
* :heavy_check_mark: [**ligh7hau5**](https://github.com/vulet/ligh7hau5): A Matrix to Fediverse / ActivityPub client / bridge. Also, some media proxying. `GPL-3.0, Javascript`
* :heavy_check_mark: **[Nautilus](https://github.com/aaronpk/Nautilus)**: A standalone service to deliver posts from your own website to ActivityPub followers. `Apache-2.0, PHP`
* :heavy_check_mark: **[PeerTube (on Matrix) Search](https://github.com/vranki/hemppa#peertube-search)**: Search PeerTube via Matrix, using Sepia Search API to search on all participating public PeerTube instances. You can also select any single instance. It's implemented as a module for Hemppa the bot. `GPL-3.0, Python`
* :heavy_check_mark: [**RSS-to-ActivityPub Converter**](https://github.com/dariusk/rss-to-activitypub): Convert any RSS feed to an ActivityPub actor that can be followed by users on ActivityPub-compliant social networks like Mastodon. `MIT, Javascript`
* :heavy_check_mark: **[YouTube2PeerTube](https://github.com/mister-monster/YouTube2PeerTube)**: A bot that mirrors YouTube channels to PeerTube channels as videos are released in a YouTube channel. `AGPL-3.0, Python`
* :black_nib: [**ActivityPubSchema**](https://github.com/redaktor/ActivityPubSchema): JSON Schema definition of the ActivityStreams and ActivityPub specifications. `MIT, Javascript`
* :black_nib: [**FediHealth**](https://git.feneas.org/buttle/fedihealth): Software to help you define federation policies for your node. `AGPL-3.0, Python`
* :heavy_check_mark: [**Mastodon Bot Autoresponder**](https://github.com/drequivalent/mastodon-bot-autoresponder) ([Fedi account](https://mastodon.ml/@drq)): a bot that implements group functionality in Mastodon. `MIT, Python`
* :heavy_check_mark: [**Pherephone**](https://github.com/writeas/pherephone): An ActivityPub server that reblogs all the statuses of certain actors. You set it up to follow a few accounts and it announces everything they post. `AGPL-3.0, Go`
* :heavy_check_mark: [**tags-pub**](https://gitlab.com/evanp/tags-pub): Provides hashtag objects on the ActivityPub network. `Apache-2.0, Javascript`
* :heavy_check_mark: [**yt2pt**](https://github.com/buoyantair/yt2pt): A simple set of scripts to quickly import your youtube channel to peertube. `MIT, Javascript`
* :heavy_check_mark: [**activitypub-mock**](https://gitlab.com/evanp/activitypub-mock): A mock ActivityPub server to use in testing code `Apache-2.0, Javascript`
* :black_nib: [**dfk-ap**](https://glitch.com/edit/#!/dfk-ap?path=README.md%3A1%3A0) ([site](https://tinysubversions.com/notes/activitypub-tool/)): A small ActivityPub debugging server on Glitch `MIT, Javascript`
* :heavy_check_mark: [**FediDB**](https://fedidb.org/about): A suite of tools for AP devs to help make it easier to test and validate your implementation with existing implementations like Mastodon, PeerTube, Pixelfed and Pleroma `-, -`
* :black_nib: [**Sepia Search**](https://framagit.org/framasoft/peertube/search-index/) ([site](https://sepiasearch.org/)): A search engine of PeerTube videos and channels Developed by Framasoft `AGPL-3.0, Typescript`
* :heavy_check_mark: [**Share Buttons**](https://git.fsfe.org/FSFE/share-buttons): Share buttons that support dynamic input of Fediverse URLs and require no Javascript. `AGPL-3,0, PHP`
* :heavy_check_mark: [**Share Freedom**](https://gitlab.com/mugcake/share-freedom-extension): Firefox toolbar extension to share the current browser tab to the Fediverse `GPL-3.0, Javascript`
* :black_nib: [**Mastodon Simplified Federation**](https://github.com/rugk/mastodon-simplified-federation): Simplifies following and interacting with remote users on other Mastodon instances. `ISC, Javascript`
* :heavy_check_mark: [**ForgeFed**](https://notabug.org/peers/forgefed), formerly GitPub ([site](https://forgefed.peers.community), [Fedi account](https://floss.social/@forgefed)): A set of extensions to ActivityPub for federation between code forges (i.e. git hosting sites like GitLab, Gogs, Gitea, etc. Reference implementation is [Vervis](https://dev.angeley.es/s/fr33domlover/p/vervis)). `CC0-1.0`
* :heavy_check_mark: [**LitePub**](https://github.com/litepub/litepub) ([Fedi account](https://pleroma.site/users/kaniini)): A set of extensions to AP, being developed by devs from Pleroma and Mastodon (status: for the most part litepub group folded back into SocialCG, see: [issue](https://github.com/litepub/litepub/issues/6))
* :heavy_check_mark: [**NodeInfo2**](https://git.feneas.org/jaywink/nodeinfo2): An effort to create a standardized way of exposing metadata about a server. Helps expose ownership and organization details, usage statistics and protocol capabilities. `CC0-1.0`
* :black_nib: [**The did:orb Method**](https://trustbloc.github.io/did-method-orb/) ([github](https://github.com/trustbloc/did-method-orb)): A DID Method for a fediverse of interconnected nodes and witnesses.
* :black_nib: [**Content-addressible RDF**](https://openengiadina.net/papers/content-addressable-rdf.html): A scheme based on RDF allowing for data to be referred to by an identifier determined by the data itself (written by @pukkamustard of [openEngiadina](https://openengiadina.net), specification now part of [DREAM](https://dream.public.cat/pub/dream-data-spec))
* :black_nib: [**Encoding for Robust Immutable Storage** (ERIS)](https://inqlab.net/projects/eris/): ERIS is an encoding of arbitrary content into a set of uniformly sized, encrypted and content-addressed blocks as well as a short identifier (a URN) (written by @pukkamustard of [openEngiadina](https://openengiadina.net), specification now part of [DREAM](https://dream.public.cat/pub/dream-data-spec)).
* :black_nib: [**Distributed Mutable Containers** (DMC)](https://inqlab.net/projects/dmc/): Distributed data structures that can hold references to content while allowing replicas of the data structures to diverge and merge without conflict (developed by [DREAM](https://dream.public.cat/pub/dream-data-spec))
