Single-SPA Deployment

Deployment Overview

At its core, deployment is about doing one thing well inside your single-spa project. Once you understand the pattern, you can apply it consistently across features and teams.

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

# each micro frontend publishes its own bundle + import-map entry
@org/checkout -> https://cdn.example.com/checkout/v3/checkout.js

# update only this app's import-map entry to release it
{ "@org/checkout": "https://cdn.example.com/checkout/v3/checkout.js" }

Deploying a micro frontend is often just updating its import-map URL.

Deployment Example

registerApplication({
  name: '@org/app',
  app: () => System.import('@org/app'),
  activeWhen: ['/app'],
});
start();

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

Single-SPA Cheatsheet

Core single-spa APIs related to deployment.

How Deployment Works in Single-SPA

Deployment is part of how single-spa lets multiple applications — even in different frameworks — coexist on one page. A root config registers each app and controls when it is active.

Deploying a micro frontend is often just updating its import-map URL.

• A root config registers apps and calls start().
• Each app exports bootstrap, mount, and unmount lifecycles.
• activeWhen decides which routes each app owns.
• Import maps resolve each app's bundle at runtime.

Practical Guidance for Deployment

For reliable micro frontends, deployment should isolate failures and keep shared state minimal. Let each team own its app end to end while agreeing on a few shared contracts.

Common Mistakes

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

Key Takeaways

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