Matrix is an open protocol for secure, decentralised communication - defining an end-to-end-encrypted real-time communication layer for the open Web suitable for instant messaging, VoIP, microblogging, forums and more. We publish Matrix as an open standard under the open governance of the non-profit Matrix.org Foundation, and release Apache-licensed reference implementations of the protocol for server, client SDKs, bots, bridges & more. Some users may recognise Matrix via client apps such as Element (https://element.io, formerly Riot).

Matrix works by replicating conversation history across servers which participate in a given conversation, ensuring that ownership of the conversation is fully decentralised: no single server owns or controls the conversation, just as git repositories are cloned equally between all participants. As a result, you can think of Matrix more like a global decentralised object database with realtime pubsub semantics, rather than a traditional message-passing protocol. The protocol defines HTTPS+JSON APIs as a baseline, but more efficient transports and encodings are supported and encouraged.

The public Matrix network on the internet has over 26M addressable users spread over ~60K servers, ranging in size from personal RPis through to massive deployments for organisations including Mozilla, the Wikimedia Foundation, German schools in Schleswig-Holstein & Hamburg, and the entirety of the French Government.

Matrix in 2021

2020 was a busy year for Matrix.

• Mozilla turned off IRC and migrated to Matrix in March: https://matrix.org/blog/2020/03/03/moznet-irc-is-dead-long-live-mozilla-matrix
• After loads of testing, we finally turned on end-to-end encryption by default for all private rooms in May: https://matrix.org/blog/2020/05/06/cross-signing-and-end-to-end-encryption-by-default-is-here
• We finally fixed our performance problems on the overloaded matrix.org server by horizontally sharding Synapse: https://matrix.org/blog/2020/11/03/how-we-fixed-synapses-scalability
• We started to see more academic research emerging on Matrix, particularly analysing the properties of state resolution (how we keep Matrix rooms securely replicated in a byzantine fault tolerant manner): https://matrix.org/blog/2020/06/16/matrix-decomposition-an-independent-academic-analysis-of-matrix-state-resolution
• Dendrite (our next-gen Golang Matrix server) entered beta in October, steadily improving ever since: https://matrix.org/blog/2020/10/08/dendrite-is-entering-beta
• Gitter joined Matrix in October, with native Matrix support launching in December: https://matrix.org/blog/2020/12/07/gitter-now-speaks-matrix
• We started working on Decentralised Reputation as a mechanism for empowering users to filter out abuse or other unwanted content in Matrix (thus *finally* catching up with our FOSDEM 2017 talk on the subject: https://archive.fosdem.org/2017/schedule/event/matrix_future/): https://matrix.org/blog/2020/10/19/combating-abuse-in-matrix-without-backdoors
• We launched Cerulean, a wildly experimental proof-of-concept to experiment with threads demonstrate the viability of twitter-style microblogging on Matrix (including an initial implementation of decentralised reputation!): https://matrix.org/blog/2020/12/18/introducing-cerulean
• We got the first messages flowing over Decentralised MLS (Messaging Layer Security), giving logarithmic rather than linear complexity E2EE.

In 2021, we plan to add:

• Spaces - shareable hierarchies of rooms, effectively making Matrix a decentralised hierarchical filesystem for realtime data!
• Threads - full support for free-form threaded conversations
• Full Social Login (log in via Github, Gitlab, or as wide a choice of SSO providers as you like)
• Massively improved VoIP
• Voice messages, Location sharing, Custom emoji, Canonical DMs...
• ...and reworking E2EE, again, to improve reliability and performance.