There is more to Redis than just caching.

Redis can be used in a variety of scenarios as shown in the diagram.

• Session

  We can use Redis to share user session data among different services.

• Cache

  We can use Redis to cache objects or pages, especially for hotspot data.

• Distributed lock

  We can use a Redis string to acquire locks among distributed services.

• Counter

  We can count how many likes or how many reads for articles.

• Rate limiter

  We can apply a rate limiter for certain user IPs.

• Global ID generator

  We can use Redis Int for global ID.

• Shopping cart

  We can use Redis Hash to represent key-value pairs in a shopping cart.

• Calculate user retention

  We can use Bitmap to represent the user login daily and calculate user retention.

• Message queue

  We can use List for a message queue.

• Ranking

  We can use ZSet to sort the articles.