Remote Application

Remote Application Overview

Remote Application lets you structure Module Federation work so it stays readable, testable, and easy to scale. Instead of ad-hoc code, you follow a clear pattern that other developers can recognise immediately.

The key is to keep remote application focused and predictable. Start from the minimal example here, then layer in only the complexity your feature actually needs.

// remote (webpack.config.js)
const { ModuleFederationPlugin } = require('webpack').container;

module.exports = {
  plugins: [
    new ModuleFederationPlugin({
      name: 'catalog',
      filename: 'remoteEntry.js',
      exposes: {
        './ProductList': './src/ProductList',
      },
      shared: ['react', 'react-dom'],
    }),
  ],
};

A remote exposes modules through remoteEntry.js so hosts can load them at runtime.

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

Module Federation Cheatsheet

Key Module Federation settings related to remote application.

How Remote Application Works in Module Federation

Remote Application 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.

A remote exposes modules through remoteEntry.js so hosts can load them at runtime.

• 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 Remote Application

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

Key Takeaways

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