Angular 21: The "zoneless" and AI-first revolution

If 2024 was the year of Signals, 2026 is the year Angular officially sheds its legacy skin. With the release of Angular 21 in late 2025, Google has delivered what many are calling the "clean slate" version of the framework.

Angular 21 isn't just a collection of small tweaks; it’s a fundamental shift in how applications are built, tested, and maintained. Here is a breakdown of the groundbreaking features in the latest version.

1. Zoneless by default

For a decade, zone.js was the engine under Angular's hood, intercepting asynchronous events to trigger change detection. In Angular 21, Zoneless is the new default for all new projects.

• Why it matters: Applications are now faster, bundle sizes are smaller (by about 13kb), and the ExpressionChangedAfterItHasBeenChecked error is finally a thing of the past.
• The mechanism: Change detection is now entirely driven by Signals, allowing Angular to know exactly which component needs to update without checking the entire tree.

2. Signal forms (experimental)

The most anticipated feature in years has finally arrived. Signal Forms provide a reactive, type-safe alternative to the traditional Template-driven and Reactive Forms.

import { form, field } from '@angular/forms/signals';

const loginForm = form({
  email: field('', [Validators.required, Validators.email]),
  password: field('')
});

// Access values directly as signals!
console.log(loginForm.value().email);

By using Signals instead of RxJS observables for form state, you get automatic type inference and a significantly flatter learning curve for complex, nested forms.

3. AI-powered development: the MCP server

Angular 21 is the first major framework to ship with a dedicated Model Context Protocol (MCP) Server. This is a game-changer for anyone using AI coding assistants (like Cursor, GitHub Copilot, or Gemini).

• Context Injection: The MCP server feeds the latest Angular documentation, best practices, and your local project structure directly to your AI agent.
• One-Click Migrations: Instead of manually fixing breaking changes, you can ask your AI to "Migrate this component to Signal Forms," and the MCP server provides the exact, schema-correct transformations.

4. Testing Overhaul: Vitest replaces Karma

The era of the "Karma browser window" is over. Vitest is now the official default test runner for the Angular CLI.

Existing projects can use the new migration schematic: ng generate @angular/core:karma-to-vitest.

5. Angular Aria: headless accessibility

Building accessible UI components (like modals, tabs, and comboboxes) from scratch is notoriously difficult. Angular 21 introduces @angular/aria, a library of "headless" components in developer preview.

• Logic only: It handles all the ARIA roles, keyboard navigation, and focus management.
• Total styling freedom: Unlike Angular Material, Aria doesn't come with CSS. You bring your own styles (or Tailwind) and apply them to the accessible primitives.

6. Smaller, Quality-of-Life updates

• Regex in templates: You can now use Regular Expressions directly in @if and @for blocks without helper functions.
• HttpClient by Default: No more provideHttpClient() boilerplate; it is now available in the root injector by default.
• Generic SimpleChanges: ngOnChanges now supports generic types, giving you full TypeScript safety when checking for input changes.

Summary of the shift

The transition from Angular 20 to 21 represents the framework's "clean-up" phase. By removing the dependency on zone.js, swapping Karma for Vitest, and moving toward a Signal-based architecture, Angular has become as lightweight and performant as modern alternatives like Svelte or Solid, while keeping its enterprise-grade structure.