When integrating with an external API in AngularJS, the typical format used for data exchange is JSON (JavaScript Object Notation). JSON is a lightweight and readable data interchange format that is easy to work with in JavaScript applications. AngularJS developers often parse JSON responses from APIs and format data as JSON when making requests, ensuring compatibility and efficient data transfer.

AngularJS handles data binding within expressions through two-way data binding. Two-way data binding enables automatic synchronization of the model and view, allowing changes in one to instantly reflect in the other and vice versa. This feature simplifies the development process by reducing the need for manual updates and enhancing the responsiveness of AngularJS applications. Understanding how two-way data binding works is crucial for efficient data management in AngularJS.

The Routing feature in AngularJS allows for dynamic loading and rendering of views based on application state. AngularJS provides a powerful routing mechanism that enables developers to define routes, associate them with templates and controllers, and navigate between different views. Proper usage of routing enhances the structure and navigation flow of AngularJS applications, making it a fundamental concept for building single-page applications (SPAs).

In advanced AngularJS applications, "controller-as" syntax is used for controller aliasing to enhance readability. It allows you to avoid scope-related issues and makes it clear which controller is associated with a particular section of the view. The "controller-as" syntax is considered a best practice for maintaining clean and readable code in AngularJS.

Modules are a key AngularJS concept that helps in preventing scope conflicts in large applications. Modules provide a way to organize and structure an AngularJS application by encapsulating related components. They help in managing dependencies, defining reusable code, and enhancing modularity. Understanding how to use modules is fundamental for building scalable and maintainable AngularJS applications.

In AngularJS, errors while making HTTP requests to an external API can be handled using error callback functions. When working with promises, developers can attach an error callback to handle any errors that occur during the HTTP request. This ensures a graceful handling of errors and provides an opportunity to notify users or take appropriate actions based on the error type. Understanding how to handle errors in asynchronous operations is a critical skill for AngularJS developers working with external APIs.

AngularJS optimizes DOM manipulation using directives like ng-show and ng-if by employing Virtual DOM manipulation. Instead of directly manipulating the actual DOM, AngularJS creates a virtual representation of the DOM in memory. Changes are made to this virtual DOM, and then AngularJS efficiently updates the actual DOM based on the differences. This minimizes the number of DOM manipulations, leading to better performance in AngularJS applications.

The $scope object in AngularJS contributes to the two-way data binding mechanism by facilitating communication between the Controller and the View. It serves as a bridge, allowing changes in the View to automatically update the Model and vice versa. Understanding the role of $scope is crucial for building dynamic and responsive applications with bidirectional data binding in AngularJS.

Improper use of dependency injection in AngularJS, such as injecting unnecessary dependencies into components, can lead to performance issues. This can result in increased memory consumption and slower application performance. It's essential to understand the appropriate use of dependency injection to optimize performance in AngularJS applications.

In large AngularJS applications, deeper scope hierarchies can have negative implications on performance. This is because the $digest cycle needs to traverse through the entire scope hierarchy to detect and update changes. Deeper hierarchies result in more watches to check, leading to increased computational overhead. Optimizing scope hierarchy is crucial for maintaining optimal performance in large AngularJS applications.