Architecture overview

MOQOM is a publish/subscribe media system. Publishers push media to a relay; the relay forwards it to every subscriber that asked for it. There is no mixing and no transcoding in the relay: it forwards encoded objects.

flowchart LR
    subgraph Pub["Publisher device"]
        Cam["Camera / mic"] --> Enc["Encode<br/>H.264 · HEVC · Opus"]
        Enc --> SF1["SFrame<br/>(optional E2EE)"]
    end
    subgraph Relay["MOQOM relay"]
        In["Session<br/>auth · quotas"] --> Cache["Group cache<br/>(join on keyframe)"]
        Cache --> Fan["Fan-out"]
    end
    subgraph Subs["Subscribers"]
        S1["Viewer"]
        S2["Viewer"]
        S3["Cohost"]
    end
    SF1 -- "MOQT over QUIC" --> In
    Fan -- "MOQT over QUIC" --> S1
    Fan -- "MOQT over WebTransport" --> S2
    Fan -- "MOQT over QUIC" --> S3

Media model

Media over QUIC organises media as:

• Namespaces — a room is a namespace prefix under your tenant; each participant publishes under their own namespace within it. Joining a room means subscribing to its prefix, so every participant who goes live — including later arrivals — is discovered automatically.
• Tracks — one per media stream (e.g. a video quality, an audio stream, a catalog describing what a participant publishes).
• Groups and objects — a group begins at a keyframe; objects are the frames or packets within it.

What a relay does

Behaviour	Effect
Upstream deduplication	Each track is pulled from the publisher once, whatever the audience size
Join on a keyframe	New subscribers receive the group in progress, so playback starts cleanly
Bounded retention	Recent groups are cached (by groups, bytes and seconds) so reconnects and late joiners can catch up
Slow viewers isolated	One slow subscriber never stalls the room or the publisher
Per-request authorisation	Every subscribe and publish is checked against the client’s token
Quotas	Per device and per user, on sessions, subscriptions, announcements and fetches
Publisher stop	Viewers are told explicitly when a publisher ends
One UDP port	Raw QUIC and WebTransport (HTTP/3) share it

Because end-to-end encryption covers only payloads, all of the above keeps working in encrypted rooms.

Room presence and state

Participants appear in a room by announcing under its namespace; watchdogs (recorders, classifiers) are disclosed separately as room state and never appear in the roster. Room state — grants, mutes, stage, spotlight — is shared with every participant, and a client returning from a network outage recovers it exactly rather than guessing from who happens to be publishing.

Scale-out

flowchart TB
    subgraph Region["Region"]
        LB["UDP load balancing"] --> R1["Relay"]
        LB --> R2["Relay"]
    end
    P["Publishers"] --> LB
    R1 --> V1["Viewers"]
    R2 --> V2["Viewers"]

A single relay uses multiple SO_REUSEPORT sockets on one port to spread receive load across cores. Global steering across regions is in development.

Where MOQOM runs

We plan to partner with Cloudflare, Google Cloud, AWS and other CDNs and content providers. We don’t wait to ship: MOQOM runs on Google Cloud today, and you can self-host relays anywhere. No partnership is signed yet.

Continue with Control plane vs media plane and Standards.