Angular Zoneless Change Detection

What is Zoneless Change Detection in Angular?

Zoneless Angular removes zone.js and relies on signals and explicit notifications to know when to update. It cuts bundle size, removes the monkey-patching of browser APIs, and makes change detection far more targeted.

Zoneless Change Detection example

// app.config.ts
export const appConfig: ApplicationConfig = {
  providers: [provideZonelessChangeDetection()],
};

// and remove zone.js from the polyfills in angular.json

Key points to remember

• Requires state to be expressed as signals, or components to notify Angular explicitly.
• Removes roughly 30 kB of zone.js from the bundle.
• The async pipe and signals both work correctly under zoneless.
• Code that mutates plain class fields and relies on zone.js will stop updating.

Common mistakes with Zoneless Change Detection

• Switching a large legacy application over at once — migrate to signals first.
• Third-party libraries that assume zone.js is present.