The Desi Architect
Notes / Design Interview Problems / How an Ecommerce Platform Grows to 100 Million Users
Track 5 · Design Interview Problems

How an Ecommerce Platform Grows to 100 Million Users

From a single store on one database to 100 million accounts handling festival flash sales without inventory races or database overload.

How an Indian retail platform scales from 10,000 to 10 crore users, decoupling catalog browsing with CDN edges, isolating search via an outbox event stream, managing cart holds vs checkout claims, and defending database shards during flash sales.

Interview problem45 min read
On this page
  1. Why this problem is hard
  2. What are we building?
  3. Entities, API and numbers
  4. Building it up, one step at a time
  5. Where it gets hard
  6. Failure modes at a glance
  7. The whole picture
  8. How interviewers judge this
  9. Questions that come next
  10. Saying it out loud in 45 minutes
  11. Sources and assumptions