The tutorial demonstrates how to use a web browser to write and execute TypeScript code to access online APIs, specifically the BlockFacts API for cryptocurrency data. It covers the basics of APIs, including what they are, how to make API calls, and the importance of security measures such as authentication and rate limiting. The tutorial also introduces the concept of static typing in TypeScript, which helps prevent errors by enforcing type constraints during development. Additionally, it showcases how to use JSX for building user interfaces and how to use arrow functions and typed functions for better code organization and maintainability.