Design a URL Shortener
Company: Hackerrank
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Design a URL shortening service similar to Bitly.
The system should support:
- Creating a short URL for a given long URL
- Redirecting a short URL to the original long URL
- Optional expiration time for links
- Very fast redirects and high availability
Discuss the following:
- Functional and non-functional requirements
- Public APIs
- Data model
- How to generate unique short codes
- Read and write paths
- Storage and caching choices
- How to scale to very high read traffic
- Handling hot links, abuse, expiration, and basic analytics
Quick Answer: This question evaluates a candidate's ability to design scalable, highly available distributed systems, covering competencies in API design, data modeling, storage and caching strategies, unique code generation, and operational concerns such as expiration, abuse mitigation, and analytics.