Design Search Infrastructure for mobile apps

Last updated: July 24, 2025

Quick Overview

Design a event-driven search system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

HRT
System Design
Software Engineer
HRT
July 24, 2025
Software Engineer
System Design Round
System Design
Easy

46

6

2,433 solved


Design a event-driven search system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

ML system design at HRT goes beyond model selection. This System Design Round question evaluates your ability to design end-to-end ML pipelines, from data collection to model serving, while considering production constraints like latency and reliability.

What the Interviewer Expects
  • Map the business problem to a concrete ML objective
  • Propose reasonable features and a baseline model
  • Discuss basic model evaluation metrics
  • Outline a simple serving architecture
Key Topics to Cover
ML objective formulation and metric selection
Data collection and labeling strategy
Feedback loops and model retraining
Model serving and latency optimization
Feature engineering and feature stores
A/B testing and experimentation
How to Approach This
  1. Start by clarifying functional and non-functional requirements with the interviewer.
  2. Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
  3. Draw a high-level architecture first, then deep dive into 1-2 critical components.
  4. Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
  5. Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
  • How would you handle a 10x increase in prediction requests?
  • How would you run A/B tests on different model versions?
  • How would you ensure fairness and reduce bias in the model?
Practice a Similar Problem on Codemia

Solve a related problem with our interactive workspace, get AI feedback, and view detailed solutions.

Solve on Codemia
Sample Answer
Requirements Clarification

Before diving into the architecture, clarify the scope with the interviewer. For Search Infrastructure for mobile apps, key functional requirements in...

Capacity Estimation

Estimate the scale to drive design decisions. Assume 100M DAU with an average of 10 actions per user per day = 1B requests/day ~ 12K QPS average, ~36K...


Submit Your Answer
Markdown supported

Related Questions