Build a high-throughput A/B Testing Pipeline
Last updated: October 22, 2025
Quick Overview
Design a high-throughput a/b testing system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Salesforce
System Design
Software Engineer
Salesforce
October 22, 2025Software Engineer
Technical Screen
System Design
Medium
142
8
1,114 solved
Design a high-throughput a/b testing system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Salesforce 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
Partitioning and sharding strategies
Consistency models and replication
Load balancing and horizontal scaling
Database selection and data modeling
Failure handling and fault tolerance
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 implement rate limiting to protect the system?
- What would the deployment pipeline look like for this system?
- How do you ensure data consistency across multiple services?
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Requirements
- Functional Requirements:
- Support A/B testing experiments for various features across Salesforce applications.
- Real-time tracking of user interactions and performance metrics for each var...
Capacity Estimation
- Throughput (QPS) Estimation:
- Assume Salesforce has 10 million active users.
- If 10% of users participate in A/B tests daily, that’s 1 million users.
- Assuming each user triggers 5 requ...
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