Type-safe User Authentication in SvelteKit with Lucia, Planetscale, and Upstash Redis

Lucia is a TypeScript library designed to simplify user and session management across various frameworks, with a particular focus on SvelteKit. This guide demonstrates how to implement authentication using Lucia, utilizing PlanetScale for database management and Upstash Redis for session handling. Lucia's middleware allows it to operate seamlessly with different frameworks by reading request and response objects, while database adapters facilitate user and session data storage and retrieval. The guide walks through configuring Lucia, setting up a user model with Drizzle ORM on PlanetScale, and managing sessions with Upstash Redis. It also covers creating signin and signup pages, handling requests, and setting up routes in SvelteKit. The tutorial emphasizes Lucia's ability to abstract complex authentication tasks, such as hashing passwords and managing cookies, into straightforward methods, ensuring a streamlined developer experience with robust type inference. The guide concludes with instructions for implementing a signout feature and encourages further exploration of Lucia's capabilities and community engagement through Upstash Discord and additional resources.