Twitter / X

Twitter / X

Real-time social platform with petabyte-scale data and ML ranking systems.

4 Rounds ~14 Days Hard
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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

Software Engineer • Behavioral • medium

Tell me about a time you had to ship a critical feature under an extremely tight deadline. How did you ensure quality?

#Delivery #Prioritization #Resilience
Practice
Software Engineer • Behavioral • medium

Describe a situation where you strongly disagreed with a technical decision made by leadership. How did you handle it?

#Communication #Conflict Resolution #Ownership
Practice
Software Engineer • Behavioral • hard

Tell me about a time you had to dive into an unfamiliar, legacy codebase, understand it quickly, and optimize its performance.

#Problem Solving #Optimization #Adaptability
Practice
Software Engineer • Behavioral • medium

At X, we move incredibly fast and priorities shift. How do you manage your time when everything is labeled as a P0 (highest priority)?

#Time Management #Agility #Communication
Practice
Software Engineer • Behavioral • hard

Describe a time you caused a production outage. What was the root cause, how did you fix it, and what systemic changes did you implement?

#Incident Management #Accountability #Post-mortems
Practice
Software Engineer • Coding • hard

Write a function to parse a massive log file of API requests and return the 99th percentile latency.

#Math #Sorting #Bucket Sort
Practice
Software Engineer • Coding • medium

Implement a thread-safe counter class for tracking tweet likes in a highly concurrent environment.

#Concurrency #Multithreading
Practice
Software Engineer • Coding • medium

Design a simplified version of Twitter. Implement functions to post a tweet, get the 10 most recent tweets in a news feed, follow a user, and unfollow a user.

#Hash Table #Heap #Object-Oriented Design
Practice
Software Engineer • Coding • hard

Given an array of k sorted arrays representing timelines from different users, merge them into a single sorted timeline.

#Heap #Divide and Conquer #Linked List
Practice
Software Engineer • Coding • medium

Implement a Token Bucket rate limiter class with an `allow_request(user_id)` method.

#Concurrency #Math #Design
Practice
Software Engineer • Coding • hard

Given a stream of tweets, find the top K most frequent hashtags in the last 5 minutes.

#Sliding Window #Heap #Queue
Practice
Software Engineer • Coding • medium

Find the shortest path (degrees of separation) between two users in a massive directed graph of followers.

#Graph #BFS #Bidirectional Search
Practice
Software Engineer • Coding • medium

Implement an LRU Cache to store the most recently accessed tweets.

#Hash Table #Doubly Linked List #Design
Practice
Software Engineer • Coding • easy

Given a string representing a tweet, calculate its length where URLs count as exactly 23 characters, regardless of their actual length.

#String #Parsing #Regex
Practice
Software Engineer • Coding • medium

Design an Autocomplete system for X handles. Implement `insert(handle)` and `search(prefix)`.

#Trie #String #Design
Practice
Software Engineer • Coding • easy

Given an array of tweet engagement scores (positive and negative integers), find the contiguous subarray with the maximum sum.

#Array #Dynamic Programming
Practice
Software Engineer • Coding • medium

Implement a sliding window algorithm to detect if a user has posted more than N tweets in the last M seconds.

#Queue #Sliding Window
Practice
Software Engineer • Coding • easy

Given a tree representing a tweet thread (replies to replies), write a function to find the maximum depth of the thread.

#Tree #DFS #BFS
Practice
Software Engineer • Coding • easy

You are given a list of user connections. Find the most influential user, defined as the user with the highest in-degree in the graph.

#Graph #Hash Table
Practice
Software Engineer • Coding • medium

Given a string, write a parser or state machine to extract all valid @mentions and #hashtags without using built-in regex libraries.

#String #State Machine
Practice
Software Engineer • System Design • hard

Design the X 'For You' timeline, focusing on how to handle the fan-out problem for users with millions of followers.

#Scalability #Caching #Graph Processing #Stream Processing
Practice
Software Engineer • System Design • medium

Design a distributed rate limiter for the X API to prevent abuse while allowing burst traffic for premium (X Premium) users.

#Distributed Systems #API Design #Concurrency
Practice
Software Engineer • System Design • hard

Design the Trending Topics system. How do you process millions of tweets per minute to find top hashtags in real-time?

#Stream Processing #Heavy Hitters #Data Pipelines
Practice
Software Engineer • System Design • medium

Design Snowflake: A distributed unique ID generator for tweets that is highly available and sortable by time.

#Distributed Systems #Bit Manipulation #High Availability
Practice
Software Engineer • System Design • hard

Design a View Count system for tweets that updates in near real-time and handles viral spikes without overwhelming the database.

#Event Aggregation #Caching #Database Sharding
Practice
Software Engineer • System Design • hard

Design a push notification system that alerts millions of users within seconds when a highly followed account posts a new tweet.

#Pub/Sub #WebSockets #Mobile Push
Practice
Software Engineer • System Design • hard

Design X Search. How would you index tweets to allow full-text search within seconds of posting?

#Search Engines #Inverted Index #Real-time Indexing
Practice
Software Engineer • System Design • medium

Design the Community Notes feature, including the data model for contributors, ratings, and the algorithm pipeline to display the most helpful note.

#Data Modeling #Graph Algorithms #Event Driven
Practice
Software Engineer • System Design • hard

Design an Ad Click Aggregation system that processes billions of events per day and provides real-time analytics to advertisers.

#Big Data #OLAP #Exactly-once Semantics
Practice
Software Engineer • System Design • hard

Design a system to detect and mitigate bot swarms liking a specific tweet in real-time.

#Machine Learning Infrastructure #Anomaly Detection #Stream Processing
Practice
Software Engineer • Technical • medium

Explain how you would optimize a slow-loading React component on the X web client that renders a timeline of rich media tweets.

#React #Performance #Virtualization
Practice
Software Engineer • Technical • medium

How does Redis handle memory eviction? Which eviction policy would you configure for a tweet cache and why?

#Redis #Caching #Memory Management
Practice
Software Engineer • Technical • easy

Describe the differences between TCP and UDP. Why might X use UDP for its Spaces live audio feature?

#Protocols #Networking #Streaming
Practice
Software Engineer • Technical • medium

Explain how a reverse proxy works. How does it help in load balancing and securing X's API traffic?

#Load Balancing #Security #Architecture
Practice
Software Engineer • Technical • hard

How would you profile and reduce the memory footprint of a high-throughput Go or Rust microservice handling tweet ingestion?

#Profiling #Memory Management #Go/Rust
Practice

Difficulty Radar

Based on recent AI-sourced data.

Meet Your Interviewers

The "Standard" Interviewer

Senior Engineer

Focuses on core competencies, system constraints, and clear communication.

Simulate

Unwritten Rules

Think Out Loud

Always explain your thought process before writing code or drawing architecture.

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