Design YouTube
Last updated: August 21, 2025
Quick Overview
Design the architecture for YouTube. Cover scalability, data storage, caching, and real-time requirements.
Google
System Design
Product Manager
Product Manager
System Design Round
System Design
Medium
2
13
3,565 solved
Design the architecture for YouTube. Cover scalability, data storage, caching, and real-time requirements.
System design interviews at Google 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
Monitoring, logging, and alerting
High-level architecture and component design
Partitioning and sharding strategies
Message queues and async processing
Security and authentication
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 a 10x increase in traffic overnight?
- What happens if one of your database nodes goes down?
- How would you implement rate limiting to protect the system?
- How would you handle schema migrations with zero downtime?
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Requirements
Functional Requirements
- Video Uploading: Users should be able to upload videos in various formats and resolutions.
- Video Streaming: Provide adaptive bitrate streaming for different d...
Capacity Estimation
Back-of-Envelope Calculations
- User Base: Assume 2 billion monthly active users, with 1 billion daily active users.
- Video Uploads: Assume 500 hours of video uploaded every minute. Tha...
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