Matrix.org's goal is to make real-time communication over IP as seamless and interoperable as email by providing the world with a new open standard which allows communication services themselves to interoperate.
For the end consumer this will mean they can choose to use their favourite app because they get the most value from it and trust the provider with their data, and still be able to communicate with friends using competing apps and services.
In practice Matrix specifies a set of pragmatic HTTP JSON APIs as an open standard, intended to be implemented on a wide range of servers, services and clients, letting developers build messaging and VoIP functionality on top of the entirely open Matrix ecosystem rather than using closed or proprietary solutions. The hope is for Matrix to act as the building blocks for a new generation of fully open and interoperable messaging and VoIP apps for the internet.
Matrix's APIs provide:
In Matrix, every user runs one or more Matrix clients, which connect through to a Matrix homeserver which stores all their personal chat history and user account information - much as a mail client connects through to an IMAP server. Conversation history is stored on all the homeservers who participate in a conversation, for as long as the users involved wish to store it. History can always be pulled in from other participants if needed - and if all the participants decide not to keep the history, it is by definition lost forever.
Just like email, you can either run your own Matrix homeserver and control and own your own communications and history or use one hosted by someone else (e.g. matrix.org) - there is no single point of control or mandatory service provider in Matrix, unlike WhatsApp, Facebook, Hangouts, etc.
We provide a reference implementation of a Matrix server called Synapse, written in Python/Twisted. The intention is to showcase the concept of Matrix, test and demonstrate the spec, and let anyone and everyone run their own homeserver and generally help bootstrap the ecosystem.
We also provide multiple Matrix SDKs and clients:
We'd like to invite you to take a look at the Matrix spec, run a homeserver, join the existing Matrix chatrooms already out there, and experiment with the APIs and the demo clients. Please let us know your thoughts on #matrix:matrix.org, the mailing list or @matrixdotorg or JIRA.