Welcome to the first step in building our Redis-based backend system. In this unit, we will focus on how to manage user data with expiration using Redis. This is a fundamental part of our project that will set the stage for more advanced features in later units.

Let's take a quick look at what you'll be building in this unit. We will focus on two key operations for managing user data:

1. Adding user data with an expiration time: This will ensure that user data is stored for a limited period and is automatically deleted afterward.
2. Retrieving user data: This operation will help us fetch the user data we previously stored.

Here's a quick example of how we will structure these operations:

You might remember the EX parameter from the previous lessons. It allows us to set an expiration time for the data we store in Redis. In this case, we are setting the expiration to 86400 seconds (one day) by passing to the command.

You've now seen the complete pattern for managing user data with expiration in Redis. The key concepts include storing JSON data with automatic expiration using the EX parameter, chaining asynchronous operations, and handling errors in an async environment.

This pattern forms the foundation of many real-world scenarios like session management, rate limiting, and temporary tokens. In the practice section, you'll implement this logic yourself, which will prepare you for the more complex features coming in later units.

Let's move on to the practice and start building!