● Free · no signup · ~5 min
Try a system design drill
One focused, interview-style prompt. Write a short answer and an AI interviewer grades it in seconds.
The prompt
An image service stores and serves originals from one regional object store; users worldwide complain about slow loads. What's the bottleneck and your fix?
Global usersDon't just say 'add a CDN' — justify it
Your answerFill in each line — schema, bullets, or prose.
Bottleneck ◯·Fix ◯·Trade-off ◯
No diagram needed for a drill — that's what the full interview is for.