Building ASP.NET Web API with .NET Core: A Comprehensive Guide

Building ASP.NET Web API with .NET Core: A Comprehensive Guide

In modern digital connectivity, resilient and scalable APIs are the foundation. ASP.NET Web API, coupled with .NET Core, provides developers with a dynamic framework, transforming the creation of high-performance APIs into an art form. APIs act as a secret language between software components and share information and functionality effortlessly.

ASP.NET ranks at 3rd place behind JavaScript and Java as the most popular server-side programming language in 2023, according to W3Techs.

It offers developers a versatile toolkit for building APIs, including RESTful APIs using ASP.NET Web API, ensuring efficient and scalable solutions. For instance, ASP.NET Web API with .NET Core simplifies the creation of robust web services. It allows users to search, view, and purchase books, providing fast, scalable, and cross-platform performance. This API handles user requests, retrieves data from a database, and communicates through JSON, facilitating efficient online information sharing.

Hiring .NET developers proficient in ASP.NET Web API and .NET Core becomes paramount for businesses seeking excellence. These skilled professionals develop high-performance APIs, ensuring a robust digital presence and unparalleled user experiences.

Let’s explore how to build sophisticated ASP.NET Web API using .NET Core.

Introduction to Web API and ASP.NET Web API:

APIs are the foundation for modern web applications in today’s age. APIs promote accessible communication with other apps and enable data exchange and functionality integration. Web APIs facilitate this communication over the Internet, enabling web applications to interact with external services and resources.

What is a Web API?

A Web API is a set of procedures and tools for developing web software applications. It helps build accessible communication between different software through a standardized language, typically HTTP (Hypertext Transfer Protocol). Web APIs enable third-party integrations, connect mobile apps to servers, and provide data and services to various client applications.

ASP.NET Web API: A Deeper Dive

ASP.NET Web API, created by Microsoft, is a tool for making services that websites, mobiles, and computers can use. It helps develop RESTful APIs using the .NET platform.

Check out our blog – Transforming from .NET Framework To .NET Core

ASP.NET Web API Architecture

The architecture of ASP.NET Web API revolves around HTTP requests and responses. When a client application sends an HTTP request to a Web API endpoint, the routing system processes the request, which maps the request to a specific controller and action method. The controller processes the request, interacts with the underlying data source (such as a database), and prepares the HTTP response to send back to the client.

Here's a concise table summarizing the ASP.NET Web API architecture:




Consumer of the Web API sends HTTP requests.


Maps URLs to controller actions.


Handles HTTP requests, and contains action methods.

Action Methods

Executes business logic based on HTTP requests.


Defines data structure for serialization.


Pre/post-processing logic (e.g., authentication).

Media Formatters

Serialize/deserialize data between .NET objects and HTTP requests/responses.


Implements authentication and authorization.


Optional components for tasks like logging and caching.


















ASP.NET Web architecture is centered around HTTP requests and responses, routing, controllers, model binding, formatters, and filters, enabling the development of efficient APIs for a wide range of applications. Understanding these concepts is fundamental to mastering the art of building scalable and reliable Web APIs with ASP.NET.

What’s the Use of ASP.NET API with .NET Core?

ASP.NET Web API with .NET Core is a robust tool for making services that websites and apps understand easily. It uses essential words like "DELETE", "POST," "GET," and "PUT" to talk to different devices, making communication smooth. Its strong routing support creates structured APIs, simplifying request handling and enhancing efficiency.

Businesses can create cross-platform mobile applications with ASP.NET Web API and .NET Core.

A travel app can provide users with consistent features and information on Android and iOS devices.

Empowering Modern Applications: Building ASP.NET Web API with .NET Core

Building ASP.NET Web API with .NET Core enables developers to create high-performance RESTful APIs for diverse client applications. Leveraging ASP.NET Core's robust features ensures efficient handling of HTTP requests, logical endpoint design, and seamless database integration. It forms a reliable foundation for modern API development with flexibility, security, and content negotiation support.

#1. Setting Up Your Environment

Ensure you have Visual Studio 2022 installed, along with Node.js for package management and Git for version control or use Visual Studio Code.

#2. Creating an ASP.NET Core Project from Scratch

Let's kickstart the process by creating a new ASP.NET Core project. 
 Open Visual Studio and start new projects. Choose the option that says "ASP.NET Core Web Application." Then, pick the one that says "API" – this is great for making smooth APIs.

#3. Integrating with SQL Server

Next, let’s integrate our API with an SQL Server database. Entity Framework Core makes this process seamless. Define your data model using C# classes, and Entity Framework Core will take care of the rest – creating database tables, relationships, and more.

#4. Creating Back-End Controllers

Create controllers to handle different resources of your API. For example, you might have controllers for managing posts, comments, and users. Implement these controllers' CRUD operations (Create, Read, Update, Delete).

#5. Designing an API to Serve Data

Follow RESTful principles to design your API. Use HTTP approaches to accomplish diverse actions. Ensure your API endpoints are logical and follow a consistent naming convention. Properly handle HTTP status codes to convey the result of each request.

#6. Writing API Documentation Using Swashbuckle and Swagger

Swagger, along with the Swashbuckle library, helps you generate interactive API documentation directly from your ASP.NET Core application. With Swagger, you can document your API endpoints, request parameters, and response types and even test your API directly from the documentation page.

#7. Consuming an API Using Web Client-Side Frameworks

Once your API is up and running, developers will want to consume it in their web applications. Provide clear and concise documentation on how to validate, make requests, and handle responses. Demonstrate how to consume your API using popular web client-side frameworks like Angular, React, or Vue.js. .NET Core introduced Minimal API, a simplified way to build APIs with minimal setup and code. Use attribute routing to define routes.

#8. Releasing and Deploying Your Web API in Production

Microsoft Azure offers seamless deployment options. Create an Azure account, set up your API's deployment configurations, and publish your API to the cloud. Azure provides scalable hosting solutions; check your traffic loads.


This guide provides you with a roadmap to craft a robust API that efficiently serves data and seamlessly integrates with client-side frameworks, ensuring a seamless user experience.

We help you through this process and offer specialized .NET development services. We empower your API development endeavors and assist in achieving excellence through our expertise! Get in touch!


Sunil Dhakne, a seasoned Project Manager with 17+ years in the IT industry, combines extensive expertise in Practice Management with a solid background in Project Management spanning over 7 years. With a focus on developing and maintaining Client/Server and Web-based Applications over years, Sunil is a proficient leader in the .NET domain.

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