Runtime Remotes

Runtime Remotes Overview

Runtime Remotes 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 runtime remotes 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.

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

Module Federation Cheatsheet

Key Module Federation settings related to runtime remotes.

How Runtime Remotes Works in Module Federation

Runtime Remotes 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 Runtime Remotes

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

Common Mistakes

• Skipping error handling and edge cases when wiring up runtime remotes.
• Leaving runtime remotes untested, so regressions slip into production.
• Over-engineering runtime remotes before you actually need the extra flexibility.
• Ignoring documentation, which makes runtime remotes hard for the next developer to change.

Key Takeaways

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