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The fetch() Handler

server.fetch is a Web-standard handler:

fetch: (request: Request) => Promise<Response>

It runs the same routing pipeline as listen() — match the route, build the request, run middleware and the handler, serialize the response — without starting a platform-specific server. Use it on any target that hands you a Request and expects a Response back instead of letting you bind a port.

Like server.inject(), it lazily bootstraps the server (imports controllers, applies plugins) on its first call.

Deno Deploy / Supabase Edge Functions​

import { Server } from "balda";

const server = new Server({ swagger: false });

Deno.serve(server.fetch);

Both platforms run on Deno, so server.listen() also works if you'd rather bind a port yourself — Deno.serve(server.fetch) is the idiomatic form these platforms expect.

Vercel / Netlify Functions (Node runtime)​

import { Server } from "balda";

const server = new Server({ swagger: false });

export default server.fetch;

A Service Worker​

self.addEventListener("fetch", (event) => {
  event.respondWith(server.fetch(event.request));
});

Controller autoloading needs a real filesystem​

controllerPatterns imports controllers by globbing the filesystem at bootstrap time. Deno Deploy and Supabase Edge Functions don't give you one — register routes and controllers explicitly on those targets rather than relying on autoloading.

What it doesn't do​

server.fetch() doesn't handle WebSocket upgrades. A WS upgrade needs the underlying platform's native upgrade mechanism (server.upgrade() on Bun, Deno.upgradeWebSocket() on Deno), which only exists once the server is actually listen()-ing on a real connection — not something a bare Request can carry. If you need WebSockets, use listen().