System Design Refresher: Efficient Short URL Generation with Redis Counters

To kick off this article, let’s dive into the problem we’re aiming to solve.

Problem Statement:

In the world of URL shorteners, generating unique and compact identifiers for long URLs is critical for ensuring quick redirection without collisions. A typical challenge arises when the system needs to confirm the uniqueness of each shortened URL, leading to additional overhead in checking existing entries in the database or cache. This problem becomes particularly pronounced in high-traffic scenarios where the application must handle millions of requests per second.

The traditional approach of checking each generated short code for uniqueness can lead to performance bottlenecks and increase latency, especially when scaling the system horizontally. For instance, a relational database or even a cache-based system like Redis could face contention when verifying the uniqueness of short codes in real-time.

This article explores a streamlined solution: leveraging Redis as a globally distributed counter to generate 7-character Base62 codes directly, ensuring deterministic and unique identifiers without the need for a costly existence check. This method not only simplifies the implementation but also enhances the scalability and reliability…