# CLI Builders

A number of Angular CLI commands run a complex process on your code, such as building, testing, or serving your application. The commands use an internal tool called `Architect` to run CLI builders, which invoke another tool (bundler, test runner, server) to accomplish the desired task. Custom builders can perform an entirely new task or to change which third-party tool is used by an existing command.

Visit the following resources to learn more:

- [@official@CLI Builders](https://angular.dev/tools/cli/cli-builder)
- [@opensource@Angular Builders](https://github.com/just-jeb/angular-builders)
- [@video@Angular Builders – Creating Custom Builder from Scratch](https://www.youtube.com/watch?v=QbDkDLnXAZE)