Design Feed Generation Infrastructure for mobile apps
Last updated: October 6, 2025
Quick Overview
Design a high-throughput feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Doordash
October 6, 202510
7
4,854 solved
Design a high-throughput feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Doordash asks this during the Onsite to assess your depth in software engineering. They want to see understanding of design patterns, system architecture, and the trade-offs involved in different technical approaches.
What the Interviewer Expects
- Design a complex system component applying multiple engineering principles
- Reason about system-level trade-offs: performance, reliability, developer experience
- Discuss advanced patterns: event sourcing, CQRS, distributed transactions
- Address cross-cutting concerns: observability, security, backward compatibility
- Demonstrate depth in both theoretical foundations and practical implementation
Key Topics to Cover
How to Approach This
- Apply SOLID principles. Single Responsibility makes code testable, Open/Closed makes it extensible.
- Choose data structures based on access patterns, not familiarity.
- Prefer immutable data and message passing over shared mutable state for concurrency.
- Design APIs with RESTful conventions, versioning, meaningful errors, and pagination from day one.
Possible Follow-up Questions
- How would you handle backward compatibility?
- What testing strategy would you use for this component?
- What are the security implications of this design?
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
Core Design Principles
For the feed generation infrastructure at Doordash, we will focus on the following core design principles:
- Separation of Concerns: By decoupling the feed generation logic from data storage and...
Architecture
The architecture of the feed generation system will be microservices-based, composed of several key components:
- Feed Generator Service: This service handles incoming requests to generate feeds...
Submit Your Answer
