Build a high-throughput Feed Generation Pipeline
Last updated: November 22, 2025
Quick Overview
Design a high-throughput feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Snapchat
System Design
Software Engineer
Snapchat
November 22, 2025Software Engineer
Onsite
System Design
Hard
470
10
1,594 solved
Design a high-throughput feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
System design interviews at Snapchat 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
- Drive the design discussion proactively with minimal interviewer guidance
- Perform detailed capacity estimation and use it to inform design decisions
- Design for global scale with multi-region deployment and data consistency
- Deep dive into 2-3 critical components with implementation-level detail
- Address complex trade-offs: CAP theorem, eventual consistency, conflict resolution
- Discuss operational excellence: deployment strategy, chaos engineering, SLOs/SLIs
- Propose a phased rollout plan from MVP to full-scale system
Key Topics to Cover
Security and authentication
Failure handling and fault tolerance
Load balancing and horizontal scaling
Consistency models and replication
High-level architecture and component design
Monitoring, logging, and alerting
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?
- What monitoring and alerting would you set up on day one?
- What happens if one of your database nodes goes down?
- How do you ensure data consistency across multiple services?
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Requirements
- Functional Requirements:
- Generate personalized feeds for users based on their interests, friends' activities, and trending content.
- Support real-time updates to feeds as new content is g...
Capacity Estimation
- User Base: Assume 300 million monthly active users.
- Daily Active Users (DAU): Estimated at 100 million, each generating an average of 20 feed requests per day.
- Total Requests: 100 mi...
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