XMPP vs Matrix
Since both protocols position themselves as federated, both protocols are compared mainly in terms of federalism and freedom. In this review, only The Matrix is considered, and not its forks like Gridify and other. Forks of the Matrix protocol can have significant differences.
|Open, extensible protocol?||Yes. It is allowed to add the protocols of other messengers to the protocol XMPP (including the Matrix protocol).||No|
|Commercial project?||No||Symbiosis Company New Vector Ltd (Riot) (provides paid services) + The Matrix.org Foundation C.I.C. (collects donations).|
|Government sponsorship?||The French government prohibits OMEMO encryption, the reason being its high level encryption and easy installation ||The French government sponsors server-side Matrix development and they also developed a Matrix client called Tchap. |
|E2E encryption?||OMEMO, OTR, OTR4, PGP ECC, PGP RSA||OLM|
|Monopoly network?||Many servers  and many clients .||Most users use only Riot + Matrix.org|
|Fault-tolerant?||Yes (2 000 000 device to 1 node)||No|
|Cost of service 1 active device||> $0.01 / mo||~ $1 / mo|
|Support for one cross-platform client? User-friendliness?||No. Lack of funding. Clients exist on all platforms, but video calls only work well on Android. The commercial XMPP messengers Zoom and WhatsApp do not participate in the federation and do not open the source code||The web client Riot is based on Chromium and has support for all operating systems that support Chromium.|
|Good sponsorship and advertising support?||No||Yes|
|Usage in big network?||XMPP is in usage by Google, WhatsApp, Zoom, IBM, LiveJournal, Nintendo, NSA, US military,Federal Police Germany  and etc... A federated network adapted for millions of private servers with any number of users. Donations can pay for the maintenance of big amateur servers.||No. In the matrix, the main load of the network is located on super-nodes that a person with a small budget cannot create. The cost of maintaining amateur supernodes does not pay off the donation.
Big supernodes must have commercial sponsors or government support to serve users
PS: The main advantages of the Matrix are good financial support that allows you to create clients for all platforms. Matrix sponsorship is based on a misconception about the unique features of the protocol. In reality, the Matrix protocol is inferior in technical characteristics to XMPP.
The correct technical solution for Matrix would not be the opposition of XMPP, but the inclusion of the Matrix protocol as an extension of XMPP. An example of such successful integration is the Conversations messenger in which as an extension XMPP was an addition to the Signal messenger protocol. The reason for the failure of the global spread of XMPP has an economic basis. A real federal system without servers of monopolists is not able to collect donations and generate significant income.
The main advantage of XMPP is the free extensibility of the protocol, which allows you to create custom extensions without the creation of infinite forks. For large companies and governments, it is preferable to use the XMPP protocol for federated communication, because they can make changes to the protocol without the participation of Matrix's owners. But in general, large companies are not commercially interested in the development of federal systems. This leads to leakage of users from large commercial servers, so most large XMPP servers with billions ( ) of users are not federated and do not invest in the development of the XMPP protocol. Federation would lead them to the loss of the userbase of commercial messengers and switching users to many personal, regional little public servers and indie-messengers.