Action — a control's outbound behavior (device → server). Declared as
action on the control; rides broadcast_request or route_msg. See
Data Flow — sync & actions.
Broadcast — fan-out delivery. A client sends broadcast_request; the relay
re-emits a broadcast frame to the channel. The backbone of telemetry.
Channel — a namespace on the relay. Members see each other's broadcasts and
can route to each other. On the gateway, channels are namespaced per account.
Connect+ gateway — the hosted, authenticated, slot-metered service wrapping
the relay; uses wss:// and a token. See Connection & Pairing.
Control — a single UI element (gauge, button, …). See Control Catalog.
Device — a phone/iPad running the CAR-TER app; a thin client that renders a
layout and speaks MeshSocket.
E2EE key — an optional shared base64 symmetric key for end-to-end-encrypted
forwarding (e2eeKey / QR k); the relay forwards ciphertext it can't read.
Editor / live-edit — a transient authoring session (started by scanning an
editor QR) where the device renders editor-pushed layouts and exposes read-back
responders. See Live Editing & the MCP Authoring Loop.
Filter — a sync field; shallow key/value match used to select which
broadcast frames a control consumes (usually keyed on msg_type).