Instagram (photo sharing)

Upload photos, store them durably and serve them to a global audience. Most bytes never touch your servers: the CDN serves views, an object store keeps the originals, and asynchronous workers produce the sizes clients ask for.

Notes and ratings save in this browser. Completing self-assessment records your progress.

Duration 45:00

Requirements checklist

Upload a photo with a caption.View photos (several sizes for different screens).List a user's photos; a feed (see the news feed case study).Like and comment (out of scope here).Image views p99 under ~200 ms worldwide — mostly a CDN problem.Uploaded photos are never lost (11 nines of durability in the object store).Upload acknowledged in a few seconds; thumbnails can appear a moment later.Very read-heavy: hundreds of views per upload.

Clarifying questions

Photo sizes and how many renditions?
Global audience?
Is video in scope?
How long are photos kept, and can they be deleted (privacy law)?

Open a practice canvas (new tab)Estimation calculators (new tab)

requirements

Suggested time: about 6 minutes. Defines what 'uploaded' means (acknowledged vs processed).

Notes for requirements