Design a large-scale URL Shortening Platform
Last updated: August 11, 2025
Quick Overview
Design a distributed url shortening system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
TikTok
August 11, 2025503
10
230 solved
Design a distributed url shortening system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during System Design Round at TikTok. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. TikTok values engineers who can think about scalability from day one.
What the Interviewer Expects
- Systematically gather requirements and estimate capacity (QPS, storage, bandwidth)
- Design a scalable architecture with clear component responsibilities
- Make well-reasoned database and caching decisions with trade-off analysis
- Address consistency vs availability trade-offs specific to the use case
- Discuss partitioning strategy, replication, and data modeling
- Cover failure handling, monitoring, and alerting strategies
Key Topics to Cover
How to Approach This
- Start by clarifying functional and non-functional requirements with the interviewer.
- Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
- Draw a high-level architecture first, then deep dive into 1-2 critical components.
- Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
- Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
- How would you handle schema migrations with zero downtime?
- How would you handle a region-wide outage?
- How would you handle a 10x increase in traffic overnight?
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Requirements
- Functional Requirements:
- Shorten long URLs into short ones, e.g.,
https://t.co/abc123 - Redirect users from short URLs to original URLs with minimal latency.
- Provide analyti...
- Shorten long URLs into short ones, e.g.,
Capacity Estimation
- Estimating Daily Requests:
- Assume TikTok has 1 billion users.
- If each user creates an average of 2 short URLs per week, that leads to about 400 million new URLs weekly.
- For ...
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