Tools
Small things I wanted while writing the articles. Everything runs in your browser — there is no backend here, nothing is uploaded, and nothing is logged.
Answer a real design prompt, then have Claude grade it against a six-part rubric — scores, gaps, and the questions an interviewer would ask next.
Practise low-level design: write notes, draw a class diagram, sketch the code, then send it to Claude for a rubric-based review — paste into claude.ai for free, or review right here with your own key.
Turn daily actives and payload size into QPS, storage, bandwidth, and cache size. The numbers that should drive a design, with latencies worth memorising.
Time a pattern against inputs of growing length to see whether it degrades exponentially. Runs in a worker, so a catastrophic pattern cannot freeze the page.