# Use the esbuild-based Angular application builder

- Status: accepted
- Date: 2026-04-26

## Context and Problem Statement

Angular 17 introduced a new application builder (`@angular/build:application`) based on esbuild and Vite, replacing the legacy webpack-based `@angular-devkit/build-angular:browser` builder. Which builder should be used for development and production builds?

## Considered Options

- `@angular/build:application` — esbuild-based (Angular 17+)
- `@angular-devkit/build-angular:browser` — webpack-based (legacy)

## Decision Outcome

Chosen option: "`@angular/build:application`", because it is the Angular-recommended builder since v17, delivers significantly faster builds, and is required for certain schema-level features such as `stylePreprocessorOptions.sass.silenceDeprecations`.

### Positive Consequences

- Build times are 3–5× faster than the webpack builder for development and production.
- Native ESM output with better code splitting.
- Aligns with Angular's recommended toolchain for v17+.

### Negative Consequences

- Webpack-specific configuration options (custom plugins, loaders) no longer apply. Not an issue for this project.
- The `sass` sub-option under `stylePreprocessorOptions` is specific to this builder's schema; the Karma test builder uses a stricter schema and does not support it.

## Pros and Cons of the Options

### `@angular/build:application` (esbuild)

- Good, because significantly faster cold builds and incremental rebuilds.
- Good, because Angular-recommended default since v17.
- Good, because required for `sass.silenceDeprecations` support.
- Bad, because webpack plugin ecosystem is not compatible.

### `@angular-devkit/build-angular:browser` (webpack)

- Good, because supports custom webpack configuration.
- Bad, because deprecated direction; slower builds.
- Bad, because does not support the `sass.silenceDeprecations` option.
