Module Federation Debugging

Debugging Overview

Debugging 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 debugging 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 ProductList = React.lazy(() =>
  import('catalog/ProductList').catch(() => ({
    default: () => <p>Catalog is temporarily unavailable</p>,
  })),
);

Always provide a fallback so a failing remote degrades gracefully instead of crashing the shell.

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

Module Federation Cheatsheet

Key Module Federation settings related to debugging.

How Debugging Works in Module Federation

Debugging 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.

Always provide a fallback so a failing remote degrades gracefully instead of crashing the shell.

• 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 Debugging

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

Key Takeaways

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