Fastify

Mount the Files gateway on a Fastify server. Hijacks the reply and bridges Fastify's raw IncomingMessage/ServerResponse to the Web Request/Response the gateway speaks.

files-sdk/fastify mounts a createFilesRouter on a Fastify server. Fastify hands you Node IncomingMessage/ServerResponse under request.raw/reply.raw, so the binding bridges them to the Web Request/Response the gateway speaks (the same Readable.toWeb/fromWeb seam as the Express adapter). reply.hijack() cedes the response to the gateway, and a client disconnect is wired through to abort the upstream read on a proxied download.

server.ts

import Fastify from "fastify";
import { createFiles } from "files-sdk";
import { s3 } from "files-sdk/s3";
import { createFilesRouter } from "files-sdk/api";
import { createRouteHandler } from "files-sdk/fastify";

const router = createFilesRouter({
  files: createFiles({ adapter: s3({ bucket: "uploads" }) }),
  allowedOrigins: ["https://app.example.com"],
  authorize: async ({ req }) => {
    /* throw to deny, or return a per-user constraint — see /ui/server/authorization */
  },
});

const app = Fastify();

// Don't let Fastify consume the body — the gateway reads the raw stream itself.
// Dropping the built-in json/text parsers routes every content type through the
// no-op catch-all, leaving the raw body intact.
app.removeAllContentTypeParsers();
app.addContentTypeParser("*", (_req, _payload, done) => done(null));

app.all("/api/files", createRouteHandler(router));

app.listen({ port: 3000 });

Fastify runs its content-type parsers before your handler, and the built-in application/json/text/plain parsers consume the request body the gateway needs — both for the JSON verbs and for the proxy/explicit-key PUT upload. Drop them (removeAllContentTypeParsers()) and add the no-op catch-all (addContentTypeParser("*", …), as above) so the raw body reaches the gateway. If you don't want that app-wide, register the route inside an encapsulated plugin with its own parsers.

See the gateway options for the full configuration and the authorize model for locking it down.