How do you design a tiny URL shortener service architecture?

System Design
Hard
Microsoft
140.5K views

A system design question requiring candidates to outline components like databases, APIs, and hashing strategies for URL reduction. It tests scalability and distributed systems knowledge.

Why Interviewers Ask This

This question assesses high-level architectural thinking and the ability to handle massive scale challenges. Interviewers want to see how you balance consistency, availability, and partitioning. It also checks your familiarity with real-world constraints like storage limits and collision handling.

How to Answer This Question

Start by clarifying requirements like read/write ratios and latency expectations. Propose a hashing mechanism (like Base62) to generate short codes. Discuss database choices for storing mappings. Address caching strategies for frequent requests. Consider load balancing and redundancy for high availability.

Key Points to Cover

  • Hashing strategy for unique short code generation
  • Distributed database for scalable storage
  • Caching layer for performance optimization
  • Load balancing for high availability

Sample Answer

To design a URL shortener, I would use a consistent hashing algorithm to map long URLs to short, unique keys. These keys could be generated using a combination of the URL hash and a counter to ensure uniqueness. The syst…

Common Mistakes to Avoid

  • Ignoring collision resolution strategies
  • Overlooking the need for a cache layer
  • Failing to specify database sharding approaches

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