Module Federation Setup

Setup Overview

Setup is a building block you will reach for often in Module Federation. It keeps related logic together and makes your intent obvious to reviewers and future maintainers.

When you learn setup properly, you avoid the guesswork that leads to bugs and rework. The example below shows the shape you will use in most real Module Federation projects.

const { ModuleFederationPlugin } = require('webpack').container;

module.exports = {
  plugins: [
    new ModuleFederationPlugin({
      name: 'shell',
      remotes: { catalog: 'catalog@http://localhost:3001/remoteEntry.js' },
      exposes: {},
      shared: { react: { singleton: true }, 'react-dom': { singleton: true } },
    }),
  ],
};

ModuleFederationPlugin configures which modules an app exposes, consumes, and shares.

Setup Example

new ModuleFederationPlugin({
  name: 'app',
  filename: 'remoteEntry.js',
  exposes: { './Widget': './src/Widget' },
  remotes: { other: 'other@http://host/remoteEntry.js' },
  shared: { react: { singleton: true } },
});

• Start from a minimal Setup example and grow it only as needed.
• Keep configuration explicit so Setup behaves the same in every environment.
• Name things clearly so teammates understand your Setup at a glance.
• Add tests around Setup early to lock in expected behaviour.

Module Federation Cheatsheet

Key Module Federation settings related to setup.

How Setup Works in Module Federation

Setup builds on Module Federation's ability to load code from another independently built and deployed application at runtime. Each app can be a host, a remote, or both.

ModuleFederationPlugin configures which modules an app exposes, consumes, and shares.

• Remotes expose modules through a remoteEntry.js manifest.
• Hosts declare remotes and import exposed modules dynamically.
• Shared dependencies are deduplicated, ideally as singletons.
• Each micro frontend builds and deploys on its own schedule.

Practical Guidance for Setup

In production, setup needs careful version management and graceful failure handling. Align shared dependency versions and always render a fallback when a remote cannot load.

Common Mistakes

• Copying setup snippets without understanding what each line does.
• Skipping error handling and edge cases when wiring up setup.
• Leaving setup untested, so regressions slip into production.
• Over-engineering setup before you actually need the extra flexibility.

Key Takeaways

• Setup is a core part of working effectively with Module Federation.
• Start small and keep setup focused on a single responsibility.
• Apply consistent patterns so setup scales across your project.
• Test and document setup to keep it maintainable over time.