🔥 Using Rspack with Express: Why You Need webpack-dev-middleware & webpack-hot-middleware

Rspack has built-in Hot Module Replacement (HMR) support — but only when using its built-in dev server (rspack-cli).

When building a custom development server with Express, Rspack does not handle HMR automatically. You must manually wire up the middleware to:

• Serve files from memory
• Watch for changes
• Push hot updates to the client

✅ Solution

Use the standard Webpack middleware packages:

pnpm add --save-dev webpack-dev-middleware webpack-hot-middleware

🧩 Why This Works

Rspack is compatible with Webpack's plugin/middleware APIs, so these official Webpack middlewares integrate cleanly. As of Rspack v0.7+, this is the recommended way to set up HMR in custom server environments.

⚠️ Deprecated

The previously used Rspack-specific packages:

• @rspack/dev-middleware
• @rspack/hot-middleware

are now deprecated in favor of the standard Webpack equivalents.