Psi is an instant messaging application for Windows, Linux, and Mac OS X that connects to the free, open XMPP network.
Google Talk, LiveJournal, and Portugal Telecom are just a few of the groups that are actively using the XMPP network around the world — and many other companies and educational institutions are still joining in. Psi allows you to seamlessly chat with anyone connected to this global IM network through services like these.
A friendly face for everyone
Whether you use Windows, Linux, or a Mac, Psi is right at home on your desktop. From the system tray icon on Windows to the dock badges on Mac OS X, Psi takes advantage of each operating system's unique features and appearance to provide a first-class IM experience on almost any computer.
And since Psi is designed to be fast and lightweight from the ground up, you're free to enjoy all of its features without slowing down the rest of your system.
Thanks to the efforts of volunteers around the world, localized versions of Psi are available in almost twenty different languages. And with its built-in support for the Unicode international text standard, Psi can also send and receive messages in virtually any language. Casually converse with accents, symbols, and right-to-left text — Psi won't miss a single stroke.
Have it your way
Psi's appearance is highly customizable, so you can choose the colors, icons, and emoticons that suit you best. With many user-contributed iconsets to choose from in the Psi community, you're sure to find a look that matches your mood and personality.
Flexibility should be more than just skin deep, of course. That's why Psi lets you tailor the interface to your liking — customize toolbars, keyboard shortcuts, and other options so you can chat just the way you like it.
Using the same SSL technology that makes it possible for you to safely shop on the web, Psi automatically encrypts its communication with compatible IM servers to provide a secure connection over untrusted networks like public WiFi access points. For advanced security needs, Psi can also encrypt messages end-to-end with OpenPGP.
Leading the way
Psi's developers are actively involved in the XMPP community, working hard to ensure that Psi fully supports the standards for features like avatars, multi-user chats (with full admin control), remote client control, and more. It's standards like these that allow people to communicate smoothly with each other on the XMPP network, and Psi ensures that you'll never miss a beat.
How can Psi be completely free of charge, with absolutely no strings attached?
Because its source code is open to contributions from volunteer programmers around the world.
For more information about the ongoing work on Psi, visit our development section.
XMPP is an open instant messaging protocol that drives the world's largest open IM network.
To learn more, visit xmpp.org.