Design a TinyURL-like short link service
Company: Bytedance
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Design a TinyURL-like service that generates short URLs and redirects users to the original long URLs.
Requirements:
- Provide APIs to create a short link and to resolve (redirect) a short link.
- Short links must be reasonably short (e.g., 6–10 characters) and unique.
- The system should handle collisions (e.g., if hashing or random IDs collide).
- Support optional TTL/expiration for short links.
- The service should be scalable and highly available.
Discuss data model, key generation strategy, storage/cache (e.g., Redis), collision handling, and how redirects work end-to-end.
Quick Answer: This question evaluates competency in system design and distributed systems, covering API design, data modeling, unique key-generation and collision handling, caching and storage choices, TTL/expiration semantics, and scalability/high-availability considerations.