ASP.NET Core Web API Tutorials

ASP.NET Core Web API Tutorials

ASP.NET Core Web API Tutorials

This ASP.NET Core Web API Tutorial will cover all the ASP.NET Core Web API concepts with real-time examples. You will learn from the basic to advanced features of ASP.NET Core Web API as you progress in this ASP.NET Core Web API Tutorial Course.

This ASP.NET Core Web API Tutorial is For whom:

This tutorial is designed for Students, Beginners, Intermediate, and Professionals Software Developers who want to learn ASP.NET Core Web API step by step from very basics to advanced level concepts. This ASP.NET Core Web API Tutorial provides a hands-on approach to the subject with step-by-step program examples that will assist you in learning and putting the acquired knowledge into practice.

Why do we need Web APIs?

Suppose you have an idea to develop and launch a product. For this, you need to develop a website and launch this product. Then what will you do? You will develop a website using any web technologies like ASP.NET MVC, PHP, ASP.NET Core, JSP, etc., that are available on the market. Of course, you will need a database, such as MySQL, Oracle, SQL Server, etc., to store your product’s business data.

Why do we need Web APIs?

So, by combining the website and the database, you will have a fully functional, dynamic website that interacts with the database. Now, after some time, your business grows. Now, along with the website, you also want Android and iOS apps. That means you want three different applications (Website, Android, and iOS) for your business. But remember, you only have one database in the backend, which stores the entire business data. So, we have three different applications and one database. So, all these three applications have to interact with the database, as shown in the below image.

ASP.NET Core Web API Tutorial

If all three applications interact directly with the database, we have some problems. Let us understand the problems first, and then we will see how to overcome the above problems.

Problems Without Web APIs:
  1. Duplicate logic for each Application: The business should have some business logic. We will write the same logic for each application type, which means repeating the same logic for each type of application. This will duplicate our code.
  2. Error-Prone Code: The business logic has been written in each type of application. We have to write the code in three different applications in our example. So, you might miss some code or logic in some applications. This will add more errors to your application.
  3. Some Front-end frameworks cannot communicate directly with the Database: If you are developing the website (i.e., front-end) using the angular framework, then the angular framework cannot communicate with the database directly. Angular is a front-end framework.
  4. Hard to Maintain: This type of structure is hard to maintain. This is because we have written the code in many places, and if we want to improve something in our application, we need to do the same thing in many places.

There are also lots of other problems that we face in this structure. Let us see how to overcome the above problems, or we can say why we need Web APIs.

Need for Web APIs:

As you can see in the image below, we have three applications on the left-hand side, and on the right-hand side, we have the database.


We aim to establish communication between all these three applications and the database. So, what will we do? We will add a new Web API Project. This Web API Project will interact with the database. All three applications will only interact with the Web API Project, as shown in the below image.

Advantages of Web API

So, the Website, Android, and iOS applications do not have direct access to the database. They only need to communicate with the Web API Project, and it is the Web API project’s responsibility to interact with the database. The entire business logic will be written in the Web API project only, so we need Web API for our project. So, Web API acts as a mediator between the Front-End and Back-End.

Advantages of Web API:
  1. Using Web API, we can avoid code duplication: We can write the logic in one place, i.e., in our Web API project, and all applications will use that logic.
  2. Extend Application Functionality: Suppose, first, we develop the website. Then, we can extend and develop an Android App. Again, in the future, if you want to add another type of application, we don’t have to write any logic.
  3. Abstraction: We have added an extra abstraction layer as we have written all the business logic in our Web API project. The logic we wrote in the Web API project will not be visible to the front-end developers.
  4. Security: None of the applications can access the database directly, and hence it provides security.
What is Web API?

API stands for Application Programming Interface. Web API is a concept (not a technology) that works on the HTTP Protocol and is used to extend the functionality of an application.

A Web API, or Web Application Programming Interface, is a set of rules and protocols that allows different software applications to communicate with each other over the internet or a network. It enables the exchange of data and functionality between various systems, using HTTP (Hypertext Transfer Protocol) as the communication protocol. 

Key Characteristics of Web APIs:
  • HTTP-Based Communication: Web APIs are designed to work over HTTP, the same protocol used for Web Browsing. This means APIs can be accessed using standard HTTP methods like GET, POST, PUT, DELETE, etc. The API endpoints are typically represented as URLs (Uniform Resource Locators).
  • Data Exchange Formats: Web APIs use standardized data exchange formats such as JSON (JavaScript Object Notation) and XML (Extensible Markup Language) to structure and transmit data between the client and server. JSON has become the most popular format due to its simplicity and ease of use.
  • RESTful Architecture: Web APIs are designed to follow Representational State Transfer (REST) principles. A RESTful API is stateless, uses standard HTTP methods, and organizes resources into a hierarchy with unique URLs for each resource.
  • Authentication and Authorization: Web APIs implement security mechanisms for authentication and authorization to ensure that only authorized clients can access resources or perform specific actions. Common authentication methods include API keys, OAuth, and JWT (JSON Web Tokens).
What is ASP.NET Core Web API?

ASP.NET Core Web API is a framework for building scalable and high-performance Restful Web Services (APIs) using the ASP.NET Core platform. It allows developers to create robust and flexible APIs that various clients can consume, such as web applications, mobile apps, desktop applications, and third-party services.

ASP.NET Core Web API is commonly used for building RESTful APIs that expose data and services over HTTP. It’s suitable for various scenarios, including building back-end services for web, mobile, and desktop applications, providing data to single-page applications (SPAs), and creating microservices that can be deployed independently.

Prerequisites to Learn ASP.NET Core Web API

Learning to develop with ASP.NET Core Web API involves understanding general development concepts and specific technologies related to Web API development. Here are the prerequisites you should cover before diving into ASP.NET Core Web API:

  • Basic Knowledge of C#: ASP.NET Core is built on C#, so a solid understanding of C# programming is essential. You should be comfortable with C# syntax, basic programming constructs like loops and conditionals, classes and objects, and more advanced concepts such as LINQ, async/await, and exception handling.
  • Understanding .NET Core Basics: Familiarity with the .NET Core framework is important. This includes understanding the .NET Core CLI, the structure of .NET Core applications, basic concepts like dependency injection, and how to use NuGet packages.
  • Understanding HTTP/HTTPS Protocols: Understanding how client-server communication works using HTTP methods (GET, POST, PUT, DELETE).
  • Understanding of RESTful Services Principles: Grasping the basics of REST, including statelessness, resource identification, and standard HTTP methods.
  • Understanding of JSON/XML: Familiarity with JSON and XML, which are commonly used for data exchange in web services.
  • Familiarity with Entity Framework Core: Entity Framework Core (EF Core) is the recommended ORM for data access in ASP.NET Core applications. Understanding EF Core for performing CRUD operations with databases is highly beneficial.
  • Basic Database Knowledge: Basic knowledge of databases, especially relational databases like SQL Server, MySQL, or PostgreSQL, is important. You should know how to design databases, write basic SQL queries, and understand concepts like tables, keys, and relationships.
  • Front-end Technologies (Optional but Helpful): While not strictly necessary for backend development, basic knowledge of front-end technologies like HTML, CSS, and JavaScript can be helpful, especially if you plan to work on full-stack applications. Familiarity with a JavaScript framework like Angular, React, or Vue.js is a plus.
  • Understanding of MVC Architecture: While ASP.NET Core Web API is more focused on APIs, understanding the MVC (Model-View-Controller) pattern, commonly used in ASP.NET Core applications, can be beneficial.
  • Basic Knowledge of Software Design Principles: Understanding basic software design principles, such as SOLID Principles and design patterns, can be advantageous in writing clean, maintainable, and scalable code.
  • Familiarity with Development Environments: Experience with an integrated development environment (IDE), preferably Visual Studio or Visual Studio Code, widely used for ASP.NET Core development.

Note: If we missed any concepts or topics in this ASP.NET Core Web API Course, please let us know by putting a comment in the comment box, and we promise you, as soon as possible, we will put an article on that topic.

Lastly, your feedback is important and means a lot to us. So, if you have a few minutes, please let us know your thoughts and feedback on this course.

Course Information

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Author: Pranaya Rout Pranaya Rout is a Senior Technical Architect with more than 11 Years of Experience, Microsoft MVP, Author, YouTuber, and Blogger eager to learn new technologies. Pranaya Rout has published more than 3,000 articles in his 11-year career. Pranaya Rout has very good experience with Microsoft Technologies, Including C#, VB, ASP.NET MVC, ASP.NET Web API, EF, EF Core, ADO.NET, LINQ, SQL Server, MYSQL, Oracle, ASP.NET Core, Cloud Computing, Microservices, Design Patterns and still learning new technologies.

ASP.NET Core Web API – Basics

ASP.NET Core Web API – Routing

ASP.NET Core Web API – Return Types and Status Codes

ASP.NET Core Web API – Model Binding

Automapper in ASP.NET Core Web API

HTTP Methods in ASP.NET Core Web API

Converting Console App to Web API App

ASP.NET Core Web API – Middleware

Microservices in ASP.NET Core

Popular ASP.NET Core Web API Books

Online ASP.NET Core Training Program

15 thoughts on “ASP.NET Core Web API Tutorials”

  1. Hi, any update on course completion? Eagerly waiting for entire course as your tutorials are easy to understand.

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