ownCloud.org free and open-source, allows anyone to install and operate for free on a private server, with no limits on storage space or the number of connected clients.
Pydio, formerly AjaXplorer a mature open source software solution for file sharing and synchronization. Windows, Mac, Linux, iOS, Android.
Seafile a file hosting software system. Files are stored on a central server and can by synchronized with personal computers and mobile devices via the Seafile client. Windows, Mac, Linux, iOS, Android. Server: Linux, Raspberry Pi, Windows.
Tahoe-LAFS decentralized cloud storage system. It distributes your data across multiple servers. Even if some of the servers fail or are taken over by an attacker, the entire file store continues to function correctly. Windows, Mac, Linux.
Bitmessage Wiki a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities.
Chat Secure free and open source messaging app for iOS and Android.
Cryptocat open source web and mobile application intended to allow secure, encrypted online chatting.
Discord All-in-one voice and text chat for gamers that’s free, secure, and works on both your desktop and phone.
jitsi.org | free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application. Windows, Mac, Linux.
Linphone open source SIP Phone and a free voice over IP service. iOS, Android, Windows Phone, Linux, Windows, Mac, Browser (Web).
Pond fully decentralized and distributed email system.
RedPhone on Android provides end-to-end encryption for your calls. Both must have the app installed.
JonDo Live-CD / DVD a secure, pre-configured environment for anonymous surfing and more. Based on Debian GNU/Linux.
Puppy Linux a lightweight Linux distribution that focuses on ease of use and minimal memory footprint. The entire system can be run from RAM.
Tails a live operating system, that you can start on almost any computer from a DVD, USB stick, or SD card. It aims at preserving your privacy and anonymity.
Tiny Core Linux a minimal Linux OS focusing on providing a base system using BusyBox and FLTK. The distribution is notable for its size (15 MB) and minimalism, with additional functionality provided by extensions.
Mailpile modern, fast web-mail client with user-friendly encryption and privacy features.
Mozilla Thunderbird a free, open source, cross-platform email, news, and chat client developed by the Mozilla Foundation. Thunderbird is an email, newsgroup, news feed, and chat (XMPP, IRC, Twitter) client.
Whiteout Mail open source email solution with strong end-to-end encryption that is really easy to use and runs on all of your devices.
Encryptr a free, open source password manager and e-wallet. Zero-knowledge. Cloud-based. Private.
KeePass a free open source password manager, which helps you to manage your passwords in a secure way.
LastPass remembers your passwords so that you can focus on the more important things in life.
Master Password an ingenious password solution that makes your passwords impossible to lose. Passwords aren't stored: they are generated on-demand from your name, the site and your master password.
Password Safe allows you to safely and easily create a secured and encrypted user name/password list.
SuperGenPass a bookmarklet and runs right in your Web browser. It never stores or transmits your passwords, so it’s ideal for use on multiple and public computers. It’s also completely free and open-sourced on GitHub.
git-annex allows managing files with git, without checking the file contents into git. While that may seem paradoxical, it is useful when dealing with files larger than git can currently easily handle, whether due to limitations in memory, time, or disk space.
SparkleShare creates a special folder on your computer. You can add remotely hosted folders (or "projects") to this folder. These projects will be automatically kept in sync with both the host and all of your peers when someone adds, removes or edits a file.
Syncany An open-source cloud storage and filesharing application. Securely synchronize your files to any kind of storage!
Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it's transmitted over the Internet.
EtherCalc data is saved on the web, and people can edit the same document at the same time; changes are instantly reflected on all screens. Work together on inventories, survey forms, list management, brainstorming sessions and more!
Etherpad a highly customizable Open Source online editor providing collaborative editing in really real-time.
Panopticlick tests your browser to see how unique it is based on the information it will share with sites it visits.
ProtectedText open source web application. Encrypts and decrypts text in the browser, and password (or it's hash) is never sent to the server - so that text can't be decrypted even if requested by authorities. No cookies, no sessions, no registration, no user tracking.