Design Facebook Status Search is a very popular system design interview question.

Facebook provides a search bar at the top of its page to enable its users to search posts, statuses, videos, and other forms of content posted by their friends and the pages they follow.

Key Features

Given that it will be a 45-minute interview round, you will be designing a system with a lower feature set. In this question, you will be asked to develop the backend of a system with the following key features:

1. Enable the users to search the statuses that their friends and the pages they follow have posted on Facebook.
2. For simplicity, consider that these statuses will only contain text for this particular question.

Detailed Framework

You can use the following framework to better answer the Design Facebook Status Search question in the interview. It will help you to maintain focus and answer it better.

1. Key Features
   • As discussed above
2. Design Goals
   • Minimum Latency
   • High Availability
   • Partition Tolerance
   • Eventual Consistency (CAP Theorem)
   • Read vs. Write Heavy
3. Scale Estimation
   • Daily Active Users (DAUs)
   • Read QPS
   • Write QPS
   • Data generated each day and over 10 years (Storage Utilization)
   • Approximate number of servers required
4. REST APIs
   • /statusSearch (Read API)
   • /postStatus (Write API)
5. High-Level Design
   • How to build the Search Index for fast retrieval on a large scale?
6. Application Layer
   • Multiple Stateless Servers with Load Balancer (Round-Robin)
7. Database + Search Index Design (Data Layer)
   • Schema design
   • SQL vs. No-SQL
   • Sharding
     • Hash-based sharding
     • Consistent Hashing
   • Replication (for Fault Tolerance)
   • Quorum
     • Read + Write Consistency
8. Caching for Fast Retrieval
   • Eviction Policy - LRU
9. Detailed Architecture Diagram

Optional

If time permits, you can also discuss the following towards the end of the interview:

1. Security, for example, ACL (Access Control List)
2. Statuses which can also contain media (photo & video) along with text

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Preparation Material for this question

⬇ High-Level Design + Detailed Architecture Diagram + Framework to answer this question in the interview

Learn more about the Key Features, Design Goals, Scale Estimations, REST APIs, High-Level Design, and Detailed Architecture Diagram of this problem in this video.

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Cracking the Facebook Behavioral Interview

If you have not read our first article on Top Facebook Behavioral Interview Questions, we recommend reading it by clicking the below link:

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Cracking the Facebook System Design Interview

In case if you have not read our series on Cracking the Facebook System Design Interview, we recommend reading it by clicking the below link:

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🚀 Complete SWE Interview Course [💰 Limited Time 10% offer]
🙋‍♀️ Behavioral Interview Guide [💰 Special Discount]
📚 Recommended Interview Preparation Book (on Amazon)

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