Vite Monorepo - Allow Parent Directory Access with server.fs.allow

Problem

In a monorepo, when a sub-package imports shared modules from a parent directory, Vite blocks it: The request url is outside of Vite serving allow list.

Solution

// vite.config.ts
import { defineConfig } from 'vite';
import { sveltekit } from '@sveltejs/kit/vite';
import path from 'path';

export default defineConfig({
  plugins: [sveltekit()],
  server: {
    port: 5174,
    fs: {
      allow: [
        // allow parent directory access (monorepo root)
        path.resolve(__dirname, '..'),
      ],
    },
  },
});

Key Points

• Vite blocks file access outside the project root for security. In monorepos, this becomes a problem since shared packages live in parent directories.
• Adding a path to server.fs.allow enables serving files from that directory. .. allows one level up.
• This setting only affects the dev server (vite dev), not production builds. The bundler handles it during build.