Environment Configuration

Environment Configuration Overview

At its core, environment configuration is about doing one thing well inside your Module Federation project. Once you understand the pattern, you can apply it consistently across features and teams.

Good environment configuration pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

# each micro frontend deploys independently
catalog:  https://cdn.example.com/catalog/remoteEntry.js
checkout: https://cdn.example.com/checkout/remoteEntry.js

# the host resolves remotes from a runtime manifest
{ "catalog": "https://cdn.example.com/catalog/remoteEntry.js" }

Independent deployment is the core benefit: each remote ships on its own schedule.

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

Module Federation Cheatsheet

Key Module Federation settings related to environment configuration.

How Environment Configuration Works in Module Federation

Environment Configuration 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.

Independent deployment is the core benefit: each remote ships on its own schedule.

• 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 Environment Configuration

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

Key Takeaways

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