Draft Spec Proposes Unified Server-Side HTTP API for JS Runtimes

Node.js, Deno, Bun, and Cloudflare Workers all build on Fetch's Request and Response for server-side HTTP, but they've diverged sharply on handler signatures, WebSocket upgrade flow, lifecycle management, and unmodeled features like trailers, informational responses, and extended CONNECT. This draft specification proposes a server-side API that closes those gaps without extending or subtyping the standard Fetch types.

The core idea is a separate ServerContext object that holds connection metadata, server capabilities, and lifecycle hooks like waitUntil — keeping the HTTP message itself clean while the processing environment lives elsewhere. The design depends on two proposed Fetch Standard additions currently before WHATWG: trailer support and an onInformation callback for informational responses.

The spec deliberately excludes routing, middleware, and response helper methods, leaving those to frameworks. It defines two conformance layers: a mandatory core handler model, and an optional infrastructure layer covering serve(), Server, and Listener — letting platform-managed runtimes like Cloudflare Workers and self-managed ones like Node.js both conform. The goal is portable handler code across runtimes and headroom for future protocols like WebTransport and HTTP Datagrams without breaking API changes.