Design a large-scale URL Shortening Platform
Last updated: May 29, 2026
Quick Overview
Design a event-driven url shortening system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Twilio
May 29, 2026207
8
2,604 solved
Design a event-driven url shortening system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
System design interviews at Twilio typically last 45-60 minutes. You are expected to drive the conversation, starting from requirements gathering through to a detailed architecture. The interviewer will evaluate your ability to handle ambiguity and make practical engineering decisions.
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
- What happens if one of your database nodes goes down?
- How would you handle a region-wide outage?
- How would you migrate from a monolithic to a microservices architecture?
- How would you optimize costs as the system scales?
Practice a Similar Problem on Codemia
Solve a related problem with our interactive workspace, get AI feedback, and view detailed solutions.
Solve on CodemiaSample Answer
Requirements
Functional Requirements:
- URL Shortening: Users can submit a long URL to receive a shortened version.
- Redirection: The shortened URL should redirect users to the original URL when acc...
Capacity Estimation
For this URL shortening service, let’s estimate the capacity:
- Expected Users: 10 million users.
- Requests per User: Assume an average of 10 URL shortenings per user per month.
- **Total Req...
Submit Your Answer
