Substrate model

Why ‘substrate’ rather than ‘channel’ — and the 23 substrates first-class in the EnfinitOS type system.

A substrate is the physical or virtual surface a piece of content is rendered on. EnfinitOS treats substrates as first-class type citizens — adding a new one is configuration, not a rewrite.

The 23 substrates

Category	Substrates
Out-of-home	DOOH
Visual	CTV, MOBILE, SOCIAL_FEED, GAMING
Spatial / wearable	GLASSES, AR_CONTACTS, HUD, VOLUMETRIC, HOLOGRAM, WEARABLES, AMBIENT, NEURAL
Streaming & audio	STREAMING, AUDIO
Messaging	MESSAGING
Environment	AUTOMOTIVE, SMART_HOME
Movement	ROBOTICS, DRONE
Broadcast / transit	SATELLITE, AVIATION, MARITIME
Special	ANY

Substrate-specific constraints

Each substrate brings constraints the platform must respect. The constraint types are themselves first-class in the type system:

• Spatial constraints — geofences, polygons, altitude bands.
• Temporal constraints — windows, blackout periods, quiet hours.
• Audience constraints — age, consent, opt-out registries.
• Content constraints — substrate-appropriate format and policy.
• Territory constraints — broadcast / streaming territories.
• Behavioural constraints — automotive speed gates, drone altitude / no-fly zones, robotics kinematic envelopes.
• Broadcast footprint claims — satellite beam coverage.
• Audio attention constraints — voice-assistant prominence.
• Opt-out registry constraints — TCPA, PECR, DNC, CASL.
• Consent records — first-class auditable consent objects.

Why this matters for the SDK

Render SDKs compose the substrate-agnostic Renderer Core. They don’t inherit from it; they compose it. The Drone SDK composes the Robotics SDK, not the other way around. Adding a new substrate means adding a new SDK with its substrate constraints and adapter shims — the underlying rights / proof / metering plane doesn’t change.

Substrate readiness

Per-substrate shipping readiness is tracked openly in the substrate readiness matrix on the public developer hub.