M

Meta

Hard
11Challenges
3War Rooms
~38hPrep Time
1/11Completed

Fast-paced product engineering at massive scale. Speed and clarity matter.

9% complete
Interview rounds:Coding ×2System DesignBehavioralCross-Functional

DSA2

Optimal Server Rack Cooling (Two Pointers)Given an array of server rack heights, choose two racks such that, combined with the floor…
Mid~30 min
UI Component Tree ReconstructionGiven two integer arrays `preorder` and `inorder` where `preorder` is the preorder travers…
Senior~50 min

War Room1

Replication Lag causing Stale ReadsUsers are complaining that when they update their profile picture, it still shows the old …
Mid~20 min

System Design3

Design a Global Chat App (WhatsApp)Design 1-on-1 messaging for 1 billion users. Messages must be delivered in real-time, and …
Senior~60 min
Design Instagram (Photo Feed)Design a photo-sharing platform that lets 500M users upload images, follow others, and see…
Senior~60 min
Design a Distributed File System (GFS/HDFS)Design Google File System (GFS). Store exabytes of data across thousands of commodity mach…
Senior~60 min

Tech Debt Tribunal2

React Prop Drilling HellcurrentUser flows as a prop through App -> Layout -> Sidebar -> NavMenu -> Avatar. Adding …
Junior~30 min
Missing React Error BoundaryA single unhandled exception in a data table component crashes the entire React app — whit…
Junior~20 min

War RoomMeta-specific3

Feed Ranking RegressionA model weight update in the News Feed ranking pipeline degraded engagement by 11% within …
P0+1400 XP
WhatsApp Delivery Receipt StormA bug in delivery receipt batching is causing a 400x fan-out amplification on message acks…
P1+1100 XP
Graph Write AmplificationA new social graph mutation is creating unexpected write amplification — every friend conn…
P1+1000 XP