● 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

Estimate the write QPS, read QPS, and 5-year storage for a URL shortener. Show your assumptions and math.

100M new links / month100:1 read:write~500 bytes/record

Your answerFill in each line — schema, bullets, or prose.

Assumptions ◯·Math ◯·Result ◯

No diagram needed for a drill — that's what the full interview is for.