SvelteKit, a JavaScript framework, can be used to create authentication systems using cookies. This article explains how to implement user authentication in SvelteKit by leveraging cookies, including handling login/logout functionality and protecting routes. It covers using JSON Web Tokens (JWT) to store user data, decoding JWT on both frontend and backend, and securing routes by enforcing authentication. The tutorial provides code snippets and explains the step-by-step process to create a fully functional authentication system in SvelteKit.