Networking

Networking is each platform’s own HTTP client, driven from native and surfaced as browser APIs. ScreenKit owns no HTTP, WebSocket or cookie implementation on Apple or Android: name resolution, connection pooling, HTTP/1.1 and HTTP/2, redirects, Content-Encoding, proxies, certificate verification against the system trust store, and the cookie store are all the OS’s.

Platform	Client	Cookie store
Apple	NSURLSession	`NSHTTPCookieStorage`
Android	OkHttp, over JNI	`android.webkit.CookieManager`
Linux	a vendored cpp-httplib, behind the same seam	an in-memory RFC 6265 jar

No networking or TLS library is bundled, and no CA roots ship.

What you get

const res = await fetch('https://api.example.com/shows', {
  headers: { Authorization: `Bearer ${token}` },
  signal: controller.signal,
})
const shows = await res.json()

fetch with Headers, Request, Response, AbortController / AbortSignal, FormData, and streaming request and response bodies over ReadableStream. Also the whole of XMLHttpRequest (upload progress included), WebSocket, EventSource, a cookie jar, URL and URLSearchParams.

Package-asset URLs read from the package rather than the network.

Linux is the exception, and only for the protocol

React Native has no Linux target and the distributions have no client to point at, so Linux gets a vendored cpp-httplib — one MIT header pinned by sha256 — behind the same seam. The rules that matter still hold: TLS is the image’s own OpenSSL and the roots are the image’s own CA bundle, found at run time and never shipped. An image without libssl fails at configure time rather than falling back to plaintext.

What does not survive the substitution is recorded rather than worked around:

No HTTP/2 on Linux.
No WebSocket extensions there, so no permessage-deflate (NSURLSession and OkHttp both offer it).
Cookies there are the one jar left in the tree, which also makes it the one place where cookie name prefixes and the secure-origin rule are ours to enforce.

Absent

WritableStream and TransformStream (so no pipeTo / pipeThrough), byte streams and BYOB readers, synchronous network XHR, and document.cookie.

HTTP/2 and proxies are no longer absent and no longer ours — they are whatever the platform’s client does.