---

title: Deno category: Deploy order: 5

import Link from "../../../../components/Link.jsx";

Deno

To deploy as a standalone Deno server, use the built-in deno adapter. This adapter uses Deno's native Deno.serve() API with edge-compatible fetch handlers and build-time static route mapping.

<Link name="installation"> ## Installation </Link>

You need Deno installed on your system:

curl -fsSL https://deno.land/install.sh | sh

No additional packages are needed - the adapter is built into @lazarv/react-server.

When you run a production build with Deno, the deno adapter is automatically detected and used — no configuration is needed. If you want to be explicit or need to pass options, you can add the adapter to your react-server.config.mjs file:

export default {
  adapter: "deno",
};

<Link name="configuration"> ## Configuration </Link>

You can customize the adapter by passing options:

export default {
  adapter: [
    "deno",
    {
      name: "my-app", // Application name (used in generated deno.json)
    },
  ],
};

Configuration Options

• name: Application name. Falls back to package.json name (without scope) or "react-server-app".

Environment Variables

The generated server supports the following environment variables at runtime:

• PORT: Server port (default: 3000)
• HOST: Server hostname (default: 0.0.0.0)
• ORIGIN: Override the origin URL for the server

<Link name="how-it-works"> ## How it works </Link>

The Deno adapter uses an edge build mode, bundling your entire server into a single file. At build time, it:

1. Bundles your server code into .deno/server/.react-server/server/edge.mjs
2. Copies all static assets into .deno/static/
3. Generates a start.mjs script with a build-time static route map that serves static files using Deno.readFile() with proper MIME type detection
4. Creates a deno.json with a start task for easy deployment

Static files (HTML, CSS, JS, images, etc.) are resolved from the build-time route map and served directly without going through the server handler.

<Link name="build"> ## Build </Link>

Build your application using the react-server CLI:

pnpm react-server build [root]

This produces a .deno/ directory with the following structure:

.deno/
├── start.mjs          # Entry point with static route map
├── deno.json          # Deno configuration with start task
├── static/            # All static assets
│   ├── assets/        # Hashed build assets (CSS, JS)
│   ├── client/        # Client-side bundles
│   └── ...            # Public files, pre-rendered HTML
└── server/
    └── .react-server/
        └── server/
            └── edge.mjs  # Bundled server

<Link name="deploy"> ## Deploy </Link>

Start the production server using the CLI:

deno run -A npm:@lazarv/react-server start

Or run it directly without the runtime installed:

deno run --config .deno/deno.json --allow-net --allow-read --allow-env --allow-sys .deno/start.mjs

Or use the --deploy flag to build and immediately start:

pnpm react-server build [root] --deploy

You can also use the generated deno.json task:

cd .deno
deno task start

<Link name="deployment-targets"> ## Deployment targets </Link>

Since the Deno adapter produces a self-contained server, you can deploy it anywhere Deno runs:

• Bare metal / VPS: Copy the .deno/ directory and run deno task start
• Deno Deploy: Deploy using deployctl — see the Deno Deploy docs
• Docker: Use the official Deno Docker image
• Fly.io: Deploy with flyctl using a Dockerfile
• Railway, Render: Point the start command to deno run --allow-net --allow-read --allow-env --allow-sys .deno/start.mjs

Example Dockerfile

FROM denoland/deno:latest
WORKDIR /app
COPY .deno/ .
EXPOSE 3000
CMD ["deno", "task", "start"]