What to work through
Work through a photo sharing app as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Scroll a feed of photos from followed accounts, more loading as the reader goes
- Open one photo on its own page with its caption, likes and comments
- Upload a photo with a caption, seeing progress and then the post
- Like a photo and comment on it
Constraints to discuss
- The first photo shows within 2.5 seconds on a phone
- Images never push the page around as they load: layout shift of 0.1 or less
- A phone never downloads a desktop-size image
- An upload survives a dropped connection without starting over
- A tap answers within 200 milliseconds
Need a starting point?
Watch for these common gaps as you prepare:
- Lazy-loading the first photo on screen
- Images with no width and height, so the feed jumps as they load
- One large file sent to every screen
- An upload in one request that starts over after a drop
- Ignoring the rotation stored in a phone photo, so it shows sideways
- Keeping location data from the photo after upload
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.
- Roblox: A May 2026 tip from a frontend candidate: design a photo sharing app like Instagram, in a round that was mostly about the frontend. A separate January 2026 onsite tip says the interviewer asked to treat the backend as a black box.
- Rippling: A July 2024 tip from a frontend candidate in the Marketing org: the system design round was to build Shutterstock, a stock photo site.
- Robinhood: Listed by PracHub in April 2026 as a Frontend Engineer onsite question, a photo album app with uploads and sync across devices, with no candidate narrative.