YOUR BRIEF
What to work through
Work through instagram as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Upload a photo with a caption
- Follow other users
- See a feed of photos from followed users, newest first
- Open a photo at full size
BEFORE YOU START
Constraints to discuss
- Read-heavy: far more feed views than uploads
- Feed loads in under 500 ms
- An uploaded photo is never lost
- A new post may take up to 1 minute to reach followers’ feeds
Need a starting point?
Watch for these common gaps as you prepare:
- Pushing photo bytes through the app servers
- Storing photos in the database
- Fanning out a post before its upload has finished
- Writing a big creator’s post to millions of feeds from one host
Why this question is in the collection
These sources connect the problem to company interview reports or preparation guides. They do not guarantee what a company will ask you.