Design a large-scale Search Platform
Last updated: September 11, 2025
Quick Overview
Design a low-latency search system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Zscaler
System Design
Software Engineer
Zscaler
September 11, 2025Software Engineer
Technical Screen
System Design
Medium
14
14
1,339 solved
Design a low-latency search system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Zscaler asks this during the Technical Screen to assess your architectural thinking. They want to see how you decompose a complex problem, choose appropriate technologies, and reason about failure modes. Strong candidates proactively discuss monitoring, alerting, and operational concerns.
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
Database selection and data modeling
Failure handling and fault tolerance
API design and rate limiting
Partitioning and sharding strategies
Load balancing and horizontal scaling
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 do you ensure data consistency across multiple services?
- How would you migrate from a monolithic to a microservices architecture?
- What would the deployment pipeline look like for this system?
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Requirements
- Functional Requirements:
- Users should be able to perform keyword searches across a variety of indexed data types (e.g., documents, logs, user activity).
- The system should return se...
Capacity Estimation
- Estimating QPS and Data Storage:
- Assuming Zscaler has 1 million users, with 10% active users at peak times, we estimate 100,000 concurrent users.
- If each user performs an average o...
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