In the vast landscape of the internet, long URLs can often resemble tangled webs, making sharing cumbersome and inefficient. Enter the humble URL shortener service, a nifty tool that transforms lengthy links into compact, shareable snippets. Inspired by the likes of TinyURL, let's embark on a journey to design a scalable URL shortener service that can stand the test of time.

Business Requirements:

• User Registration and Authentication: Users should be able to sign up and log in securely to manage their URLs.
• Customization Options: Allow users to create custom short URLs and set preferences like link expiration dates.
• Analytics and Reporting: Provide users with insights into link performance, including click counts and geographic distribution.
• Scalability and Performance: Ensure the service can handle high traffic volumes efficiently without compromising speed.
• Reliability and High Availability: Maintain uninterrupted access to shortened URLs through robust redundancy and failover systems.

Technical Needs:

• Highly Available Infrastructure: Utilize cloud-based or distributed systems for high availability.
• Scalable Database Solution: Implement a database capable of handling large volumes of data and high throughput.
• Efficient Shortening Algorithm: Develop or choose an algorithm for fast and unique URL shortening.
• Redundant Data Storage: Ensure redundancy and replication to prevent data loss.
• Caching Mechanisms: Use caching to improve performance and reduce latency.
• Load Balancing: Distribute traffic across servers for even workload distribution.
• Rate Limiting and Throttling: Implement mechanisms to prevent abuse and ensure fair usage.
• Security Measures: Apply encryption, access controls, and other security measures.
• Monitoring and Alerting: Set up systems to monitor performance and detect issues.
• Scalable Architecture: Design architecture that can grow and adapt to future needs.

High Level Design

Improve the System

• There is only one WebServer which is single point of failure (SPOF)
• System is not scalable
• There is only single database which might not be sufficient for 60 TB of storage and high load of 8000/s read requests

What algorithm to use for shortening URL?

One commonly used algorithm for shortening URLs is the Base62 encoding algorithm. Here's how it works:

• Generate a Unique Identifier: Start with a unique identifier for each URL, such as an auto-incrementing integer or a hash of the original URL.
• Convert to Base62: Convert the unique identifier to a Base62 string. Base62 encoding uses the characters [a-zA-Z0-9] to represent numbers in base 62 (0-9, a-z, A-Z), resulting in a shorter representation compared to using only decimal digits.
• Shorten the URL: Use the Base62 string as the shortened URL. This string is typically appended to the domain of the URL shortener service.

For example:

• Unique Identifier: 12345
• Base62 Encoding: 12345 -> "3D7"
• Shortened URL: "https://example.com/3D7"

What database to use?

For a URL shortener service, considering the need for fast retrieval and scalability, NoSQL databases like MongoDB or key-value stores like Redis are commonly used due to their high performance and flexibility. These databases excel in handling large volumes of data and offer efficient lookup operations, making them ideal choices for storing mappings between original URLs and their shortened versions. Additionally, they can be easily scaled horizontally to accommodate growing traffic and data storage requirements.

Conclusion

In the vast expanse of the internet, a scalable URL shortener service plays a vital role in simplifying and streamlining the sharing of links. By leveraging modern technologies and best practices in system design, we can build a service that not only meets the demands of today but also scales gracefully to meet the challenges of tomorrow. So, the next time you encounter a lengthy URL, remember: with a little bit of magic from our URL shortener service, sharing links becomes as easy as a click of a button.