Blasta is a collaborative bookmarks manager for organizing online content. It allows you to add links to your personal collection of links, to categorize them with keywords, and to share your collection not only among your own software, devices and machines, but also with others. What makes Blasta a collaborative system is its ability to display to you the links that other people have collected, as well as showing you who else has bookmarked a specific link. You can also view the links collected by others, and subscribe to the links of people whose lists you deem to be interesting. Blasta does not limit you to save links of certain types; you can save links of types adc, dweb, ed2k, feed, ftp, gemini, geo, gopher, http, ipfs, irc, magnet, mailto, monero, mms, news, sip, udp, xmpp and any scheme and type that you desire.
Blasta is a federated bookmarking system which is based on XMPP and stores bookmarks on your own XMPP account; to achieve this task, Blasta utilizes XEP-0163 (Personal Eventing Protocol) and XEP-0060 (Publish-Subscribe). Blasta operates as an XMPP client, and therefore, does not have a bookmarks system nor an account system, of its own.
Blasta has a database which is compiled by aggregating the bookmarks of people who are participating in the Blasta system, and that database is utilized to relate accounts and shared links.
A decentral federated small trade platform. Think Craig's List.
Populus-Viewer is a tool for decentralized social annotation, built on pdfjs, wavesurfer.js and the Matrix protocol. You can use it to read PDFs, listen to audio, or watch videos, and have rich discussions in the margins, with your friends, classmates, or scholarly collaborators.
Each uploaded file is attached to a matrix space, and each annotation to the file becomes a room within that space. Populus-Viewer has been tested with synapse and dendrite, but should be compatible with any spec-compliant matrix server.
Delta Chat is like Telegram or Whatsapp but without the tracking or central control. Delta Chat does not need your phone number. Uses the most massive and diverse open messaging system ever: the existing e-mail server network. Chat with anyone if you know their e-mail address, no need for them to install DeltaChat! All you need is a standard e-mail account. Full clients for multiple platforms available.
Github: https://github.com/deltachat/
A Matrix server written in C++. Uses Boost, RocksDB, and Sodium for its back end. Currently implements all of the Matrix spec; implementing IRC is next.
Dendrite will be a Matrix server written in Go. Requires Kafka (if run as a cluster of microservices) or something called Naffka (an embedded in-process workalike) if run monolithically. Requires Postgres as its back end.
Epicyon is an AGPL licensed ActivityPub protocol compliant federated social network server suitable for hosting a small number of accounts on low power systems requiring minimal maintenance, such as single board computers. It's the ActivityPub equivalent of an email server, storing posts as human readable JSON on file, rather than in a database. It also uses only a small amount of RAM.
Python, HTML+CSS. Almost no JS is used.
Has pretty much all of the features you'd expect. Has a calendar feature for local users. Has bookmarking of specific posts.
Instant messaging server. Backend in pure Go (license GPL 3.0), client-side binding in lots of different languages. Also supports gRPC and HTTP(S)+Websockets. Supports persistent storage with a back-end database.
This is not XMPP, but I added the tag so it's easier to find later.
This is also a proof-of-concept web client: https://github.com/tinode/webapp/
Ethical and privacy-conscious alternatives for websites and apps.
A federated microblogging application written in node.js. Replaces Twitter. Implements ActivityPub so it's already part of the Fediverse.
A collective aimed at activists that uses only OSS software and federated or decentralized software. Offers services that you can request accounts on or set up your own server and federate with them.