Targets and what runs where

Target	Status	Graphics	Media	HTTP
tvOS	primary	ANGLE → Metal	AVPlayer	NSURLSession
Android TV / Fire TV	shipping	native GLES 3, with a GLES 2 fallback	Media3 ExoPlayer	OkHttp
Embedded Linux (Batocera)	shipping	native GLES via Mesa	libvlc	vendored cpp-httplib
macOS	development only	ANGLE → Metal	AVPlayer	NSURLSession

The same .skpkg runs on all four.

Graphics

WebGL 2 needs GLES 3. On a GLES 2-only device getContext('webgl2') returns null and your app must feature-detect — Lightning 3 targets WebGL 1, so a Lightning UI is unaffected.

Raw GLES entry points are generated from tables rather than hand-written, and the WebGLRenderingContext object model and its validation sit above them in JavaScript.

Note

ANGLE is not yet built for Android, so the ANGLE → Vulkan and ANGLE → GLES rungs, the backend probe cache and the config override are Apple-only for now.

Linking

Every third-party dependency ships as a CI-built, checksum-verified binary. A fresh clone should reach a running app without compiling any third-party code.

	SDL3 / ANGLE	FFmpeg	Hermes	Shared between apps?
tvOS / macOS	static (xcframework)	—	static, from the RN tarball	No — Apple has no mechanism
Android	.so in the APK	—	prefab AAR	No — APK-scoped
Linux	dynamic, system-shared	the image’s own, beneath VLC	dynamic	Yes

Linux is the only platform where sharing is real: the runtime installs once as libscreenkit.so plus shared deps, and an app is a manifest, a .hbc and assets. A Batocera image with ten games carries one runtime — which works precisely because the app model already forbids per-app native code.

What has actually run on hardware

Worth being blunt about, because “builds for” and “runs on” are different claims:

Check	State
tvOS simulator (Apple TV 4K, 3840×2160)	✅ runs
Android TV emulator (screenkit-tv, Android 14 arm64)	✅ runs, APK built and installed
Raspberry Pi / Batocera	✅ video verified on device
Real Apple TV hardware	❌ never run
A physical Fire TV or Android TV	❌ never run
A GLES 2-only device (the ES 2 fallback)	❌ never exercised
armeabi-v7a	built and shipped for Fire TV, executed by nothing
x86_64 Android	not built

The composited-canvas and <iframe> paths on the SDL backends (Android, Linux) compile and are covered by tests on macOS, but have never executed on those platforms. A defect found in review — a second <iframe> embedded after a canvas had drawn would have failed on SDL and only on SDL — is the standing argument for not treating macOS coverage as coverage.

Not yet built

• texImage2D from a <video> element on any platform.
• The Suspended instance state and memory-pressure LRU escalation.
• A dev server with HMR, and the screenkit-go development client.
• Over-the-air updates: signed manifests, runtimeVersion gating, rollback.