# Design Quora: system design interview question

> A question-and-answer platform with personal discovery, correct vote state, and answer order that reflects quality.

Source: https://sysround.com/questions/design-quora
Updated: 2026-11-05


Difficulty: hard. Levels: Senior, Staff+.

## How the interviewer opens it

"Design a question-and-answer platform like Quora. Users ask questions, write answers, vote, and follow topics or people. Help users find relevant questions and useful answers."

## What to clarify first

- Users and existing content
- Read traffic
- Write traffic and content size
- Content and follows
- Vote rules
- Discovery
- Latency
- Consistency and availability
- Durability and regions
- Scope limits

## Scope of a strong answer

Core requirements:

- Publish questions and answers with topic labels.
- Vote on answers and read answers in rank order.
- Follow authors, topics, and questions.
- Find relevant questions through a personal feed and text search.

Usually out of scope:

- Ads and payments.
- Comments and private groups.
- Model training.
- The moderation review process.
- Full abuse detection.

## What interviewers probe

### Relevant question discovery

Users follow several kinds of interests. Popular topics create many updates, while repeated answers can make the same question dominate a feed.

### Vote correctness and answer quality

Vote changes must remain correct after retries. Answer order must also give useful new answers a chance without favoring raw popularity alone.

### Freshness and visibility

A question or answer appears in several public views. Edits and removals must reach those views despite delays and failed components.

## Common mistakes

- Treats discovery as a full database scan or an unexplained recommendation model.
- Assumes every topic update should immediately reach every follower.
- Stores vote totals without the user's durable vote state.
- Equates answer quality with raw vote count.
- Uses one consistency rule for content, feeds, vote state, and aggregate totals.
- Removes content from the primary store but ignores search results and cached previews.

## The bar by level

- **Senior:** Controls candidate retrieval and topic fanout cost. Handles vote retries, stable feed pages, event recovery, and content removal across derived views.
- **Staff+:** Quantifies fanout and popular-answer limits. Defines correctness boundaries during failures. Explains regional ownership, derived-view rebuilds, and quality safeguards as requirements change.

Practice this question with an AI interviewer: https://sysround.com/practice/new?problem=quora


---
SysRound (https://sysround.com) is an AI practice tool for system design interviews. It has a voice or typed AI interviewer and a shared whiteboard. At the end, you get feedback on each skill and a model answer. The AI feedback can be wrong.