Open Source Communication Software
Mailpile
Mailpile is an effort to reclaim private communication on the Internet. A project to rescue our personal lives from the proprietary cloud and prevent our conversations from being strip-mined for corporate profit and government surveillance. With Mailpile you can take e-mail back and make it yours.
phpBB
One of the world most popular, free, open-source and self-hosted forum software, written in PHP. With phpBB you can create communities that can be hosted with most hosting providers. The software package is built and designed from the ground up to to be extensible and provides customization option through themes and feature extensions through plugins. The extensive database of user-created extensions and styles database, easy of use, and the simple installation process has made phpBB a common choice among self-hosted forums and communities.
Ricochet
Ricochet is a communications application that uses the Tor network to reach your contacts without relying on messaging servers. It creates a hidden service, which is used to rendezvous with your contacts without revealing your location or IP address. Instead of a username, you get a unique address that looks like ricochet:rs7ce36jsj24ogfw.
Threema
Threema is a messenger application that puts security and privacy first. The application is designed to generate as little user data as possible. The service is fully GDPR-compliant and the company has its own servers hosted in Switzerland. With Threema you can keep in touch with friends, family and co-workers while enjoying privacy and rest assured that you personal data is not commoditized.
ZeroNet
ZeroNet is a decentralized web-like network of peer-to-peer users. It's basically BitTorrent thrown at the problem of web hosting and networking. With ZeroNet you can create open, free and uncensorable websites using cryptograic features of Bitcoin. ZeroNet uses .bit domain names and a decentralized domain regestry using Namecoin.
Libera Chat
Libera Chat is a next-generation IRC network that is free and open source, developed by similarly-spirited collaborative endeavours. Libera.Chat’s services are provided by Libera Chat, a Swedish non-profit organisation. While being operated by volunteers from all over the world.
NodeBB
NodeBB is an open source forum software powered by Node.js and supports either Redis, MongoDB, or a PostgreSQL database. With NodeBB you can self-host communities with instant interactions and real-time notifications powered with the help of web sockets. Thousands of organizations have also stared their communites with NodeBB SaaS product, free from self-service and maintinance.
Pixelfed
A free and ethical photo sharing platform, powered by ActivityPub federation protocol. Pixelfed is open-sourced software licensed under the AGPL license.
Bitmessage
Bitmessage is a decentralized, encrypted, peer-to-peer, trustless communications protocol. With Bitmessage you can send encrypted messages to a person, or to multiple subscribers.
Flarum
A free and open-source modern forum software written in PHP. With Flarum you can eaisly setup your own discussion froum and host it online.