Build a distributed Feature Flag Pipeline
Last updated: June 9, 2026
Quick Overview
Design a distributed feature flag system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Postmates
June 9, 202617
12
4,662 solved
Design a distributed feature flag system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during Onsite at Postmates. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. Postmates values engineers who can think about scalability from day one.
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
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
- What monitoring and alerting would you set up on day one?
- How would you handle schema migrations with zero downtime?
- What would the deployment pipeline look like for this system?
- How would you optimize costs as the system scales?
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
- Feature Flag Creation: Ability for users to create, update, and delete feature flags dynamically through a web interface.
- User Segmentation: Support for targe...
Capacity Estimation
- Expected Traffic: Assume Postmates has approximately 10 million active users.
- Feature Flag Requests: Each user might trigger feature flag checks about 10 times per day, leading to:
- ...
Submit Your Answer
