Design & Fix

A live system is failing. Find the cause, change the design and run it again until it holds.

Build & Test your own Design any system and stress-test it with spikes and failures. Free once a week, unlimited on paid plans
45 incidents
Status Incident Difficulty Inspired by Stars Actions
Live incident L1Album drop: the artist cache is there, but useless Easy Spotify —
Live incident L1Prime Day: a lightning deal takes down its own product page Easy Amazon —
Live incident L1Model launch: the playground returns 503s Easy OpenAI —
Live incident L1A credential-stuffing botnet hits sign-in Easy GitHub —
Live incident L1Notification emails stopped arriving Easy Slack —
Pro Start
Live incident L1CRM global search takes 12 seconds Easy Salesforce —
Live incident L1Supplier catalog photos fill the app servers' disks Easy Meesho —
Live incident L2Backup console down: one control-plane node failed Medium Rubrik —
Live incident L2"Explain my answer" calls the AI model on every single tap Easy Duolingo —
Pro Start
Live incident L2UPI payments hang while the receipt is sent Easy Razorpay —
Pro Start
Live incident L2Month-end CSV exports freeze the dashboard API Easy Stripe —
Pro Start
Live incident L29:15 a.m.: the market opens and the load balancer gives up first Easy Zerodha —
Pro Start
Live incident L2A viral board melts the image origin Medium Pinterest —
Live incident L2Orders are accepted in a second, then wait minutes to reach the dark store Easy Swiggy Instamart —
Live incident L2The primary database was wiped, and there was no live copy Easy GitLab —
Pro Start
Live incident L2Teams web: app servers are busy serving JavaScript Easy Microsoft —
Pro Start
Live incident L3AI image generation holds every request open for 12 seconds Medium Canva —
Live incident L3Jira dashboards slow down issue updates Medium Atlassian —
Pro Start
Live incident L3The match cache restarts mid-innings and every request hits the database at once Medium JioCinema —
Live incident L3Black Friday flash sale: the storefront and its database both drown Medium Shopify —