Learning series · 6 episodes · Senior / Staff / Principal
The File Left the Origin. Was It Safe to Deliver?
Six connected investigations into direct uploads, image transformations, CDN tiers, stale HTTP content, edge policies and global updates.
Start series →Follow the decisions in order
- Part 1 of 6
Senior
The browser uploaded the photo. Why is it not yet part of the account?Move upload bandwidth off the API without delegating final publication or authorization to the browser.
- Part 2 of 6
Staff
A photo was uploaded once. Why did the image service generate 40,000 files?Bound transformation cardinality and secure decoding while using source and recipe identity in derivative cache keys.
- Part 3 of 6
Staff
We put a CDN in front of storage. Why is the origin still receiving thousands of requests?Explain independent edge misses and how hierarchical caching reduces eligible repeated origin fetches.
- Part 4 of 6
Staff
The origin is down. Should the CDN show yesterday's page or return an error?Derive cache freshness and extension windows and choose a business-safe permitted staleness contract.
- Part 5 of 6
Principal
The edge lost its control plane. Why did it send users to a retired origin?Define policy-specific offline behavior using versioned, validated configuration snapshots and revocation limits.
- Part 6 of 6
Staff
One software release is 2 GB. How do you deliver it to 100 million devices?Design signed content delivery, partial resume, rollout waves and post-install health for massive downloads.