Singlefile

Experimental: This adapter is experimental and may change in future releases. It is intended for simple, single-page applications and static sites.

The singlefile adapter bundles your entire statically exported React application into a single, self-contained HTML file. All CSS and JavaScript modules are inlined — no external resources are fetched at runtime.

This is useful for:

• Offline-capable apps that work from a file:// URL or a single HTTP request
• Portable demos or prototypes you can share as a single file
• Embedding in environments where only one HTML file is allowed (e.g. email attachments, embedded webviews)

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

Add the adapter to your react-server.config.mjs file:

export default {
  adapter: "singlefile",
};

Or pass it via the CLI:

pnpm react-server build ./src/index.jsx --adapter singlefile

The singlefile adapter performs these steps during the build:

1. Static export — The "/" route is statically exported to produce index.html
2. CSS inlining — All <link rel="stylesheet"> tags are replaced with inline <style> blocks. CSS references in React Server Component flight data are converted to data: URIs
3. JS module inlining — All client-side ES modules are base64-encoded and embedded in a boot <script>. At runtime, they are decoded into blob URLs and wired up via a dynamic import map
4. Cleanup — Modulepreload hints, dev-only live-reload links, and the static import map are removed

The result is a single dist/index.html file that contains everything the app needs to render and hydrate.

Build your application:

pnpm react-server build [root] --adapter singlefile

This produces a dist/ directory containing a single file:

dist/
└── index.html    # Self-contained HTML with all CSS + JS inlined

The output file works in any of these ways:

# Open directly in a browser
open dist/index.html

# Serve with any static file server
npx serve dist

# Or with Python
python3 -m http.server 3000 --directory dist

• Single route only — Only the "/" path is exported. Multi-page applications with file-based routing are not supported.
• No server-side features — Server actions, API routes, and dynamic server rendering are not available. The output is purely static.
• File size — All assets are inlined (with base64 encoding for JS modules), so the output file will be larger than the sum of individual files (~33% overhead for JS due to base64).
• SPA mode recommended — This adapter works best with single-page applications. Use it with client components and client-side routing.