Twitter / X
Real-time social platform with petabyte-scale data and ML ranking systems.
4 Rounds
~14 Days
Hard
The Interview Loop
Recruiter Screen (30 min)
Standard fit check, behavioral questions, and resume overview.
Technical Loop (3-4 Rounds)
Deep dive into domain knowledge, coding, and system design.
Interview Question Bank
Backend Engineer
•
System Design
•
hard
Design a distributed rate limiter for the X API to handle different tiers of users (Free, Basic, Pro) with varying limits.
#Distributed Systems
#Rate Limiting
#Redis
Backend Engineer
•
System Design
•
medium
Design the 'View Count' feature for tweets that was recently rolled out. How do you ensure high throughput and low latency without overwhelming the database?
#Caching
#Event Sourcing
#Data Aggregation
Backend Engineer
•
System Design
•
hard
Design the 'For You' timeline. How do you mix algorithmic recommendations with tweets from people the user follows?
#Recommendation Systems
#Fan-out
#Machine Learning Infrastructure
Backend Engineer
•
System Design
•
hard
Design the backend for Community Notes. How do you handle concurrent edits, version history, and fast retrieval?
#Concurrency Control
#Database Design
#Eventual Consistency
Backend Engineer
•
System Design
•
medium
Design Twitter's URL shortener (t.co). Focus on high availability and analytics tracking.
#Hashing
#Database Sharding
#Analytics
Backend Engineer
•
System Design
•
hard
Design a real-time spam/bot detection system that evaluates tweets as they are published.
#Stream Processing
#Machine Learning
#Rules Engine
Backend Engineer
•
System Design
•
hard
Design the Direct Message (DM) system. How do you handle real-time delivery, read receipts, and offline users?
#WebSockets
#Pub/Sub
#Database Design
Backend Engineer
•
System Design
•
hard
Design a notification system that sends push notifications to millions of users simultaneously when a major news event occurs.
#Push Notifications
#Queueing
#Scalability
Backend Engineer
•
System Design
•
medium
Design a system to securely store and serve media (images/videos) uploaded by users.
#Blob Storage
#CDN
#Media Processing
Backend Engineer
•
System Design
•
medium
Design a Distributed ID Generator (like Snowflake) to generate unique IDs for tweets at a massive scale.
#Distributed Systems
#ID Generation
#Concurrency
Difficulty Radar
Based on recent AI-sourced data.
Meet Your Interviewers
The "Standard" Interviewer
Senior EngineerFocuses on core competencies, system constraints, and clear communication.
SimulateUnwritten Rules
Think Out Loud
Always explain your thought process before writing code or drawing architecture.