yaxim!

WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia and yes, those phones can all message each other! Because WhatsApp Messenger uses the same internet data plan that you use for email and web browsing, there is no cost to message and stay in touch with your friends.

Riot (formerly Vector) is an opensource interoperable app running on Web, iOS and Android. It is built around chat rooms, both public and private and provides messaging, filesharing, voice and video conferencing (beta on Android and web), integrations to tools like GitHub, Jira, Jenkins and much more soon. Vector is built on the Matrix.org open standard which provides bridges to other systems such as Slack, IRC and a lot more soon. One can use the hosted service or run their own. »

ChatSecure is a free and open source messaging app that features OTR encryption over XMPP. You can connect to your existing accounts on Facebook or Google, create new accounts on public XMPP servers(including via Tor), or even connect to your own server for extra security.

Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best Jabber client for Android .

Zulip is a group chat app.

Technitium Bit Chat is a secure, peer-to-peer (p2p), open source instant messenger designed to provide end-to-end encryption. Primary aim of developing this instant messenger is to provide privacy which is achieved using strong cryptography. It can be used over Internet and private LAN networks for instant messaging and file transfer.

Cyanide is Tox client for Sailfish OS .

GoldBug is a secure Instant Messenger. You can be sure with using GoldBug (GB), that no third party can look into your chat communication. Private user-to-user communication remains private. GoldBug therefore uses strong multi-encryption with different layers of modern encryption technologies of well known and revised crypto libraries (like libgcrypt (GnuPG) and OpenSSL). The app offers as well decentral and encrypted Email and decentral public E*IRC-Chat.

Dasher lets you do more than just text message. It's messaging with benefits:

Sesame is a messaging app that gives you a self-aware digital assistant to protect messages on your behalf: your own Personal Cognitive Messenger™.

Talkonaut is a free Jabber (XMPP) client for your iPhone or iPod with free peer-to-peer voice calling over Jingle Audio extension compatible with GoogleTalk™. Talkonaut can be used with any standard Jabber account like Gmail, Gizmo5™, Jabber.ru or from your corporate Jabber server. If you do not have a Jabber account yet, you can register one right from the Talkonaut. Talkonaut supports a number of XMPP extensions including multi-user conference chat (XEP-0045), file and image sharing (XEP-0047, XEP-0065), vCard based avatars (XEP-0153) and many others. »

- Qt E-Mail Client.- Build-in Encryption to secure E-Mails- Secure P2P Email from Friend to Friend without relying on a central server.- Chat and Instant Messaging is build in. Define & Add your friends.- Additionally a full decentral P2P Email-Option- Additional Security Layer with the GB-Feature for Emails.- Strong e2e Multi-Encryption (PGP-kind/AES over SSL: using libgcrypt).- Store Email for Offline-Friends in the P2P Network.- Preventing Data Retention (VDS). WoT-less.- Full decentral Email-Network using the Echo Protocol.- HTTP & HTTPS Connections.- Key- / Repleo-Exchange.- Libspoton Integration.- Open Source. BSD License. »

WowApp helps you do good through the Power of Sharing. We share all revenues with you. WowApp Messenger is free and you can receive earnings without ever spending money.

Jabbin is an original mashup of Social Network, Instant messaging and VoIP developed entirely on the widely-used and open protocol, Jingle/XMPP, and open source software, including Asterisk, Openfire and Jobill, a billing system developed by us.Jabbin make big use of online services: collabration platform, wiki, svn repo, forum.Be part of the movement: there are different ways you can get involved and be a part of our development team.