Design a URL Shortening Service (TinyURL)

To design a URL shortener like Google's, I'd first clarify that we need to support billions of daily requests with minimal latency. For the core logic, I recommend avoiding complex hashing algorithms like MD5 due to collision risks. Instead, I propose using a distributed auto-incrementing counter to generate a unique integer for every new URL. We then convert this integer into a Base62 string using characters A-Z, a-z, and 0-9. This ensures a short, human-readable code without the computational overhead of cryptographic hashing. The API would have two endpoints: a POST request to create the mapping and a GET request to retrieve the original URL. For storage, since reads vastly outnumber writes, I'd use a distributed key-value store like Bigtable. We would shard the data based on the first few characters of the short code to ensure even distribution and prevent hotspots. To handle global scale, we'd deploy multiple regions with read replicas close to users. Finally, we must implement caching at the edge using CDNs for frequently accessed links to reduce database load significantly.