Free online courseUsing the Fetch API in JavaScript and ASP.NET Core

Course Description

Modern web apps live and breathe through APIs, and knowing how to connect a JavaScript front end to a server is a must-have skill for web development. In this free course, you will learn how to use the Fetch API to communicate with an ASP.NET Core minimal Web API, turning simple HTTP requests into a clean workflow for real applications. The goal is to help you move beyond basic examples and become comfortable making requests that are reliable, readable, and ready for production-style projects.

You will start by understanding what Fetch is, how it differs from older approaches, and how its promise-based model affects the way you structure code. From there, you will stand up a lightweight ASP.NET Core API so you have a realistic backend to work with, then practice retrieving data from endpoints and interpreting the response object correctly. That includes learning how to reason about status codes, determine whether a response is truly successful, and avoid common pitfalls where an HTTP error does not automatically behave like a thrown exception.

As you progress, you will develop confidence handling different response shapes such as JSON responses with a body, empty responses, and text-only replies. You will also learn to send JSON payloads properly, set headers in a natural way, and pass the right options to fetch for POST, PUT, and DELETE operations. By the end, you will bring these pieces together to build a simple CRUD page that renders dynamic data in the browser using a templating approach, reinforcing the complete loop from UI to API and back.

This course is a practical step toward stronger front-end and back-end integration skills, ideal for learners who want to understand how modern JavaScript talks to ASP.NET Core services and how to build small features that scale into bigger projects.