Introduction
Meta (formerly Facebook) is known for its rigorous system design interviews, which are a crucial part of the software engineering interview process. The system design interview at Meta, also known as the “Pirate Interview” round, is a 45-minute session that assesses your ability to design scalable systems at scale.
This guide covers the common topics you’re likely to encounter, the interview format, and valuable resources to help you prepare effectively.
Meta System Design Interview Format
Key Characteristics
- Duration: 45 minutes
- Format: Known as the “Pirate Interview” round at Meta
- Focus: Design skills demonstration - open-ended questions that rarely require coding
- Process: Most time is spent discussing and drawing on a whiteboard or virtual board
- Purpose: Assess your ability to solve non-trivial system design problems
The interviewer will present a broad design problem and evaluate your solution based on your problem-solving approach, technical depth, and communication skills.
Common System Design Topics at Meta
Based on extensive research and analysis of Meta interview questions, here are the most frequently asked system design topics:
1. Design Facebook News Feed
The news feed is a core feature of Facebook, displaying updates from friends and followed pages in a scrollable feed.
Key Features to Design:
- Users see news feed containing posts and statuses from friends and followed pages
- Users can post and like statuses (text, images, videos)
- Users can send friend requests and follow pages
Challenges:
- Real-time feed generation
- Ranking algorithms for feed relevance
- Handling billions of users and posts
- Efficient data retrieval and caching
2. Design Facebook Status Search
Enable users to search posts, statuses, videos, and other content posted by friends and followed pages.
Key Features:
- Search service for statuses posted on Facebook
- Search within friends’ and followed pages’ content
- Text-based search (can be extended to multimedia)
Challenges:
- Indexing massive amounts of content
- Real-time search updates
- Ranking and relevance algorithms
- Scalability for millions of queries per second
3. Design Live Commenting
Design the backend for real-time commenting on Facebook posts, where users see new comments in real-time.
Key Features:
- Real-time comment feed for posts
- Users see new comments as they appear
- Handle concurrent comments from multiple users
Challenges:
- Real-time data synchronization
- WebSocket or polling mechanisms
- Handling high concurrency
- Maintaining comment order and consistency
4. Design Facebook Messenger / WhatsApp
Develop the backend of a messenger system for instant messaging.
Key Features:
- 1:1 conversations between users
- Track online/offline status
- Optional: Group conversations and push notifications
Challenges:
- Real-time message delivery
- Message persistence and ordering
- Presence/status management
- Handling millions of concurrent connections
- End-to-end encryption considerations
5. Design Instagram
Design a mobile social network for sharing photos and videos.
Key Features:
- Upload and share photos
- Follow other users
- Like photos
- Scrollable feed of photos from followed users
Challenges:
- Media storage and CDN distribution
- Feed generation and ranking
- Image processing and optimization
- Real-time updates for likes and comments
6. Design Proximity Server
Design a service to discover nearby attractions such as places and events.
Key Features:
- Add, update, and delete places
- Query nearby places within a given distance (latitude/longitude)
- Optional: Query events near a place at a specific time
Challenges:
- Geospatial indexing (GeoHash, R-trees)
- Efficient proximity queries
- Handling time-based queries
- Scalability for location-based services
7. Design Typeahead Suggestions
Design a service that suggests autocomplete search queries based on typed characters.
Key Features:
- Suggest top 10 search queries based on typed characters
- Popularity determined by search frequency
Challenges:
- Real-time suggestions
- Efficient prefix matching (Trie data structures)
- Ranking and relevance
- Handling millions of queries
8. Design Privacy Settings
Design a service that enables users to specify privacy levels for posts.
Key Features:
- Specify privacy levels for posts (Public, Friends, etc.)
- Control post visibility to specific user sets
- Basic: Public and Friends
- Advanced: Friends of friends, custom groups
Challenges:
- Efficient privacy checks
- Access control enforcement
- Querying posts with privacy constraints
- Scalability for billions of posts
9. Design Top N Songs / Trending Topics
Design a service to get top N songs (or trending topics) for a user over the past X days.
Key Features:
- Get top N songs based on listen frequency
- Time-based windowing (past X days)
- Ranking by popularity
Challenges:
- Real-time aggregation
- Efficient top-K algorithms
- Sliding window calculations
- Handling high-volume data streams
10. Design Web Crawler
Design a web crawler that downloads and indexes web pages for search.
Key Features:
- Download web pages from seed URLs
- Index pages for future retrieval
- Handle duplicate URLs
- Crawl all connected pages
Challenges:
- URL deduplication
- Respecting robots.txt
- Rate limiting
- Distributed crawling
- Handling different content types
Interview Preparation Tips
1. Understand the Format
- Practice drawing diagrams on a whiteboard or virtual board
- Focus on communication and explaining your thought process
- Be prepared for open-ended discussions
2. Master Core Concepts
- Scalability: How to handle millions/billions of users
- Caching: Redis, CDN, caching strategies
- Database: SQL, NoSQL, sharding, replication
- Load Balancing: Different algorithms and use cases
- Message Queues: Kafka, RabbitMQ for asynchronous processing
- Real-time Systems: WebSockets, server-sent events
3. Follow a Structured Approach
- Clarify Requirements: Ask questions about scale, features, constraints
- Estimate Scale: Calculate QPS, storage, bandwidth needs
- High-Level Design: Draw major components and their interactions
- Detailed Design: Deep dive into specific components
- Discuss Trade-offs: Explain design decisions and alternatives
4. Practice Common Patterns
- Feed Generation: News feed, Instagram feed
- Real-time Systems: Live commenting, chat systems
- Search Systems: Full-text search, typeahead
- Geospatial Systems: Proximity servers, location-based services
- Ranking Systems: Top-K problems, trending algorithms
Resources
Video Tutorials and Articles
The Interview Sage - Top Facebook System Design Questions
This comprehensive article provides detailed explanations of the most common Meta system design interview questions, including:
- Video explanations for each problem
- Design goals and scale estimations
- High-level design overviews
- Detailed architecture diagrams
- Additional resources for each topic
The article covers all the topics mentioned above with video tutorials and links to additional learning materials.
Community Discussions
1Point3Acres Meta System Design Discussion
This community discussion thread provides:
- First-hand interview experiences
- Specific questions asked in Meta interviews
- Tips and strategies from successful candidates
- Common pitfalls to avoid
- Additional resources shared by the community
Official Meta Resources
- Meta Careers - Software Engineering Interview: Facebook Careers Interview Preparation
- Meta Engineering Blog: Real-world system designs and engineering insights
Key Takeaways
- Meta’s system design interviews focus on real-world scale: Think about handling billions of users and massive amounts of data
- Communication is crucial: Explain your thought process clearly and discuss trade-offs
- Follow a structured approach: Requirements → Scale → Design → Deep Dive → Trade-offs
- Practice common patterns: News feeds, real-time systems, search, and geospatial queries
- Study Meta’s actual systems: Understanding how Facebook, Instagram, and WhatsApp work provides valuable insights
Conclusion
Preparing for Meta’s system design interview requires a combination of understanding core system design principles, practicing common patterns, and learning from real-world examples. The topics listed above represent the most frequently asked questions, but being well-versed in fundamental concepts will help you tackle any design problem that comes your way.
Remember: The goal is not just to design a working system, but to demonstrate your ability to think through complex problems, consider trade-offs, and communicate your solutions effectively. Good luck with your Meta system design interview preparation!