Build a scalable Ad Serving Pipeline
Last updated: January 8, 2026
Quick Overview
Design a scalable ad serving system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Goldman Sachs
January 8, 202637
10
1,659 solved
Design a scalable ad serving system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
System design interviews at Goldman Sachs 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
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?
- How would you handle a region-wide outage?
- What happens if one of your database nodes goes down?
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
- Ad Request Handling: The system must handle millions of ad requests per second and serve relevant ads based on user data and context.
- Ad Inventory Management:...
Capacity Estimation
Given that Goldman Sachs aims to serve ads globally with millions of users:
- User Base: Assume 10 million unique users.
- Requests per User: Each user makes approximately 10 ad requests per h...
Submit Your Answer
