How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

What difficulty level is this interview question?

This is a hard difficulty System Design question, commonly asked during Onsite rounds at Lyft.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Lyft during technical interviews.

Design a scalable news feed system | Lyft Interview Question

Quick Overview

This System Design question evaluates a candidate's ability to design scalable backend systems for a social app news feed, covering data modeling, API design, real-time updates, ranking, privacy controls, and operational concerns such as sharding, caching, and monitoring.

Context

You are designing the backend that powers a mobile social app's home/news feed at large scale. The system must handle high write throughput (users publishing posts) and high read throughput (users opening and scrolling feeds), while supporting real-time updates, ranking, and privacy.

Tasks

Define functional and non-functional requirements.
Propose a data model for posts, users, relationships, and feeds.
Specify core APIs: publish, follow/unfollow, getFeed (include pagination), and real-time update approach.
Compare fan-out-on-write vs. fan-out-on-read. Choose an approach under high write and read loads and justify.
Cover the following: ranking, real-time updates, deduplication, privacy/blocks, backfilling after new follows, cold-start for new users, caching, storage and indexing, sharding and partitions, consistency and ordering guarantees, failure handling, and monitoring.
Provide capacity estimates with clearly stated assumptions.
Present a high-level architecture diagram description (components and data flow).

Quick Overview

Tasks

Define functional and non-functional requirements.

Propose a data model for posts, users, relationships, and feeds.

Specify core APIs: publish, follow/unfollow, getFeed (include pagination), and real-time update approach.

Compare fan-out-on-write vs. fan-out-on-read. Choose an approach under high write and read loads and justify.

Cover the following: ranking, real-time updates, deduplication, privacy/blocks, backfilling after new follows, cold-start for new users, caching, storage and indexing, sharding and partitions, consistency and ordering guarantees, failure handling, and monitoring.

Provide capacity estimates with clearly stated assumptions.

Present a high-level architecture diagram description (components and data flow).

Design a scalable news feed system

Quick Overview

Context

Tasks

Solution

Comments (0)

Design a scalable news feed system

Quick Overview

Context

Tasks

Solution

Comments (0)

Design a scalable news feed system

Quick Overview