JS API Reference

qzjs provides a WinterTC-compatible JavaScript API. The globals listed here are available in any JS that runs in the runtime (initial_script, message handlers, and code invoked via qz_post_message), without requiring require() or import.

Architecture

API Categories

APIs fall into three groups by the standard they come from.

WinterTC (WinterCG standard)

The WinterCG-compatible subset of Web APIs qzjs implements.

API	Global
console	console
performance	performance
timers	setTimeout, setInterval, clearTimeout, clearInterval
EventTarget	EventTarget, Event, CustomEvent, ErrorEvent
AbortController	AbortController, AbortSignal, DOMException
URL	URL, URLSearchParams, URLPattern
fetch	fetch, Headers, Request, Response
crypto	crypto, crypto.subtle
streams	ReadableStream, WritableStream, TransformStream
compress	CompressionStream, DecompressionStream
TextEncoder	TextEncoder, TextDecoder
Blob / File / FormData	Blob, File, FormData
structuredClone	structuredClone
MessageChannel	MessageChannel, MessagePort
Worker	Worker
navigator	navigator

W3C APIs

Browser-standard APIs beyond the WinterCG core.

API	Global
WebSocket	WebSocket
BroadcastChannel	BroadcastChannel
EventSource	EventSource
CacheStorage	caches, CacheStorage, Cache
Service Worker	navigator.serviceWorker
localStorage	localStorage, sessionStorage

qzjs Platform Extensions

qzjs-specific APIs, not part of any Web standard. Their style is close to Node.js but they are not Node APIs (process, require, Buffer are absent).

API	Global	Notes
fs	qzjs.fs	Filesystem operations
storage	qzjs.storage	Key-value storage
serve	serve()	HTTP / WebSocket / gRPC server
grpc	grpc	gRPC client + server (QZ_WITH_GRPC=ON)

Standards Compliance

qzjs targets WinterTC compatibility — the same subset of Web APIs used by Cloudflare Workers, Deno, and other server-side runtimes. DOM-specific APIs (document, window, HTMLElement) are intentionally excluded.

Not Included

These browser APIs are explicitly excluded:

• DOM: document, window, HTMLElement, addEventListener on globals
• CSS: CSSStyleSheet, getComputedStyle, CSSOM
• Layout: requestAnimationFrame, IntersectionObserver, ResizeObserver
• Media: WebRTC, AudioContext
• Storage: indexedDB (use qzjs.storage)

Usage

All globals are available immediately — no imports needed:

// Core APIs
console.log('Hello from qzjs');
setTimeout(() => console.log('tick'), 1000);

// fetch with streaming
let response = await fetch('https://example.com/data.json');
let data = await response.json();

// crypto
let bytes = crypto.getRandomValues(new Uint8Array(32));
let hash = await crypto.subtle.digest('SHA-256', new TextEncoder().encode('hello'));

// URL parsing
let url = new URL('https://example.com/path?key=value');
console.log(url.searchParams.get('key')); // "value"

// Filesystem (platform extension)
let content = await qzjs.fs.read('/app/config.json');

// Storage (platform extension)
await qzjs.storage.set('session_token', 'abc123');