Vercel

BuildTarget.vercel emits a complete Vercel Functions workspace under .spry/vercel/. Spry generates all the wrapper files required by the platform — you deploy the workspace as-is.

Config

import 'package:spry/config.dart';

void main() {
  defineSpryConfig(
    port: 3000,
    target: BuildTarget.vercel,
    reload: ReloadStrategy.hotswap,
  );
}

ReloadStrategy.hotswap keeps the Vercel dev server alive across rebuilds.

Build output

.spry/
  src/
    main.dart               ← compile input
  vercel/
    runtime/
      main.js               ← compiled Dart-to-JS output
    api/
      index.mjs             ← Vercel Function entry point
    vercel.json             ← rewrite rules (generated if missing)
    package.json            ← @vercel/functions dependency
    public/                 ← copied public assets

api/index.mjs is a thin ESM wrapper that loads the compiled runtime and re-exports the fetch handler in the shape Vercel expects.

vercel.json is generated with a catch-all rewrite to /api so all requests are handled by the function:

{
  "rewrites": [{ "source": "/(.*)", "destination": "/api" }]
}

Deploy

# Build
dart run spry build

# Deploy from the generated workspace
cd .spry/vercel
vercel deploy

For CI deployment, keep Vercel's Root Directory as the repository root and set the Build Command to dart run spry build. Vercel will pick up vercel.json from .spry/vercel/ after the build generates it. Alternatively, run cd .spry/vercel && vercel deploy as a post-build step.

Local dev

dart run spry serve

spry serve runs vercel dev inside .spry/vercel/ automatically, including installing @vercel/functions on first run.

Good fit

• Vercel-hosted server deployments
• Teams that want zero platform glue code in their repository
• Projects deploying both static assets and a server function on Vercel