NeoChat is a free open source @matrix messaging app for Linux desktop and mobile. You can follow at:

➡️ @neochat

It's made by @kde and the official NeoChat website is at apps.kde.org/neochat

Delta Chat is a free open source encrypted messaging system that works through email (so it is federated too). You can follow at:

➡️ @delta

There are apps for Android, iPhone/iPad, Linux, Mac and Windows. More info at delta.chat

(You can also message people on conventional email accounts unencrypted.)

Dino is a free open source XMPP/Jabber messaging app for Linux and BSD desktop computers. You can follow at:

➡️ @dino

The official site is at dino.im

Dino supports end-to-end encrypted messaging through OMEMO, and they are now testing encrypted video calls too.

Jami is a FOSS encrypted peer-to-peer calling and messaging app. You can follow the project here:

➡️ @Jami

It supports video calling, voice calling and instant messaging, with a Skype-style interface.

The app is available for Android (Google Play and F-Droid), iPhone, iPad, Linux, Mac and Windows.

You can find out more from the website at jami.net

Tigase is a private company which develops free open software for instant messaging through XMPP/Jabber. You can follow them at:

➡️ @tigase

They have a number of XMPP projects including server software and apps for MacOS (Beagle), iOS (Siskin) and Android (Stork).

Their website is at tigase.net

Monal IM is a FOSS XMPP/Jabber messenger app for iPhone, iPad and Mac, you can follow it here:

➡️ @Monal

You can find out more from the official site at monal.im

Monal is available from the Apple App Store and it supports OMEMO end-to-end encryption.

Kaidan is an XMPP/Jabber app for Linux and Android, and part of the @kde project. You can follow at:

➡️ @kaidan

You can download or find out more from the website at kaidan.im

The XMPP Standards Foundation develops the XMPP/Jabber instant messaging and voice/video calling standards. You can follow them at:

➡️ @xmpp

The official site is xmpp.org

It's a free open standard, so anyone can use it in their software and hardware.

Snikket is a new XMPP/Jabber-based decentralised FOSS messenger service. You can follow at:

➡️ @snikket_im

The official website is snikket.org

It aims to make XMPP into a more viable alternative to Whatsapp etc by providing consistency in design and terminology.

(It's sort of how Mastodon made ActivityPub more mainstream, by using consistency to make it clear the instances are part of one network.)

Gajim is a free open source XMPP / Jabber app for Linux, Mac and Windows. You can follow at:

➡️ @gajim

You can download it from the official site at gajim.org

Briar is a free open source secure p2p messaging system for Android which can be used through @torproject , or locally through wifi or bluetooth. You can follow the "not-yet-official" account at:

➡️ @briar

Because it has local support, it can be used even if the internet is shut down (for example at demonstrations or in disaster zones).

It's available from Google Play and @fdroidorg , the official site is at briarproject.org

Delta Chat is a free open source encrypted messaging system that works through email accounts. You can follow at:

➡️ @delta

It's available for Android, iOS, Windows, Mac and Linux from the official site at delta.chat

Mastodon

This is a brand new server run by the main developers of the project as a spin-off of mastodon.social 🐘 It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!