Deploy a Basic App to Vercel (api/)

A file in api/ becomes a Vercel Function with no extra configuration. It receives a Web Request, so it goes straight into the chain.

Steps

Folder Structure End State

• my-project
  • api
    • index.ts

npm install @drashland/drash
npm install --global vercel

import {
  Application,
  Resource,
} from "@drashland/drash/modules/http.polyfill.js";
 
class Home extends Resource {
  paths = ["/api"];
 
  GET(request: Request) {
    return new Response("Oh so easy");
  }
}
 
const app = Application
  .builder()
  .resources(Home)
  .build();
 
export default {
  fetch(request: Request) {
    return app
      .handle<Response>(request)
      .catch(() => {
        return new Response("Sorry, but we hit an error!", {
          status: 500,
          statusText: "Internal Server Error",
        });
      });
  },
};

Verification

Run the Drash App

vercel dev

Open It

Go to http://localhost:3000/api . Pass --listen to use a different port.

Notes

The resource’s paths must match the function’s route. A function at api/index.ts is served at /api, so a resource with paths = ["/"] will never match and every request answers 404. This is the easiest thing to get wrong here — it does not come up in the other runtimes, where you own the whole URL space.

Vercel Functions run on the Node runtime, whose URLPattern support varies by Node version, so this uses the polyfill entry point.

If you are writing plain JavaScript rather than TypeScript, set "type": "module" in your package.json or name the file .mjs, because the code above uses import. The polyfill entry point also works with require() — see the CommonJS example.

This example uses the Node runtime because Vercel recommends it over the Edge runtime , and Next.js 16.3 dropped support for runtime = 'edge' on routes and pages. If you do target the Edge runtime, it provides a global URLPattern, so the native entry point applies there instead — see About > Concepts > Native vs. Polyfill.

For the other Vercel entrypoint, see server.ts.

The finished app is in the repository at examples/platforms/vercel/api.