• Understanding ASP.NET Web API: Basics of creating web services with ASP.NET.
• RESTful Services: Principles and implementation of RESTful APIs.
• Data Serialization: Automating XML and JSON data serialization and deserialization.
• Routing: Configuring API routes for accessing resources.
• HTTP Methods: Implementing CRUD operations using GET, POST, PUT, DELETE, etc.
• Content Negotiation: Handling requests for different data formats (XML, JSON).
• Model Binding and Validation: Mapping client data to models and validating input.
• Error Handling: Managing errors and exceptions in a user-friendly manner.
• Security: Implementing authentication and authorization for API access.
• Testing: Strategies for testing APIs, including unit and integration tests.
• Versioning: Managing different versions of the API.
• Documentation: Documenting the API for developers and end-users.
• Deployment: Deploying the API to servers or cloud platforms.

Before building XML/JSON APIs with ASP.NET, ensure familiarity with:

• C# Programming: Solid grasp of C# language fundamentals.
• ASP.NET Basics: Understanding of ASP.NET framework essentials.
• Web Development: Knowledge of HTML, CSS, and JavaScript.
• REST Principles: Awareness of RESTful architecture and methods.