Single-SPA with Vite

with Vite sits at the heart of build configuration in single-spa. This guide walks through the concept step by step, with examples, a cheatsheet, and common mistakes to avoid.

with Vite Overview

At its core, with vite 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 with vite pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

import { registerApplication, start } from 'single-spa';

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

start();

single-spa orchestrates multiple framework apps on one page through a root config.

with Vite Example

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

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

Single-SPA Cheatsheet

Core single-spa APIs related to with vite.

API	Example	Purpose
registerApplication	`registerApplication({ name, app, activeWhen })`	Register a micro frontend
activeWhen	`activeWhen: ['/checkout']`	Route ownership
start	`start()`	Begin routing
bootstrap	`export async function bootstrap()`	One-time setup
mount	`export async function mount(props)`	Render the app
unmount	`export async function unmount(props)`	Clean up the app
import map	`systemjs-importmap`	Locate app bundles

How with Vite Works in Single-SPA

with Vite 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.

single-spa orchestrates multiple framework apps on one page through a root config.

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 with Vite

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

Concern	Recommendation
Isolation	One app's crash should not break others
Shared state	Prefer shared utility modules over globals
Routing	Keep activeWhen rules explicit and non-overlapping
Deployment	Release via import-map updates per app

Common Mistakes

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

Key Takeaways

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

Pro Tip

Bookmark this with vite pattern and reuse it. Consistency across your single-spa codebase is worth more than clever one-off solutions.