ModuleFederationPlugin

ModuleFederationPlugin sits at the heart of webpack configuration in Module Federation. This guide walks through the concept step by step, with examples, a cheatsheet, and common mistakes to avoid.

ModuleFederationPlugin Overview

ModuleFederationPlugin 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 modulefederationplugin 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.

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

Module Federation Cheatsheet

Key Module Federation settings related to modulefederationplugin.

Option	Example	Purpose
name	`name: 'shell'`	Unique container name
filename	`filename: 'remoteEntry.js'`	Remote entry manifest
exposes	`exposes: { './X': './src/X' }`	Modules a remote shares
remotes	`remotes: { app: 'app@url' }`	Remotes a host consumes
shared	`shared: { react: { singleton: true } }`	Deduplicate libraries
lazy load	`import('remote/Module')`	Load remotes on demand
Suspense	`<Suspense fallback={...}>`	Handle async loading

How ModuleFederationPlugin Works in Module Federation

ModuleFederationPlugin 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 ModuleFederationPlugin

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

Concern	Recommendation
Shared versions	Use singletons with requiredVersion
Runtime errors	Wrap remotes in error boundaries and fallbacks
Deployment	Resolve remotes from a runtime manifest
Performance	Lazy-load remotes and cache remoteEntry.js

Common Mistakes

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

Key Takeaways

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

Pro Tip

Pair modulefederationplugin with automated tests from day one. It is far cheaper to catch Module Federation regressions in CI than in production.