{"slug": "show-hn-baserates-dev-memorize-programmer-napkin-math", "title": "Show HN: Baserates.dev, memorize programmer napkin math", "summary": "A developer launched Baserates.dev, a spaced repetition app that teaches programmers latency numbers and napkin math, inspired by Jeff Dean's famous list and Simon Eskildsen's talk. The app includes CPU instruction latencies, basic context like unit pronunciation, and uses InstantDB for guest authentication and progress saving.", "body_md": "When I began my career in programming I remember reading Jeff Dean's \"Latency Numbers Every Programmer Should Know\" [1], and getting inspired. Alas, it's been over a decade, and I never fully internalized all the numbers.\n\nUntil recently. I discovered Simon Eskildsen's talk [2] and github repo [3] on programmer napkin math. I liked his reasoning, and decided to _actually_ internalize the numbers now.\n\nSo I made baserates.dev.\n\nIt's a spaced repetition program that teaches you the napkin math from Simon, enhanced with a few things from Jeff Dean's list. The main changes: I included CPU instructions, like L1 Cache reads. I also included some nooby context, like how to pronounce the character μ, and a reminder on what is bigger: nano seconds, or micro seconds.\n\nThe app automatically saves your progress, and doesn't require auth. Most of the logic is vibe coded: I fed Claude all the links. I use InstantDB [^4] for the backend, mainly to support guest auth and saving progress. Most of my time spent on the project was just going through and making sure the numbers were right. [^5]\n\nHope you enjoy it!\n\n[1]: [https://gist.github.com/jboner/2841832](https://gist.github.com/jboner/2841832)\n\n[2]: [https://www.youtube.com/watch?v=IxkSlnrRFqc](https://www.youtube.com/watch?v=IxkSlnrRFqc)\n\n[3]: [https://github.com/sirupsen/napkin-math](https://github.com/sirupsen/napkin-math)\n\n[4]: Disclaimer: I am the founder of InstantDB\n\n[5]: One fun story: I got claude to spin up a bunch of machines on Amazon, to confirm latency numbers for same AZ, cross AZ, cross region requests.\n\nComments URL: [https://news.ycombinator.com/item?id=48624232](https://news.ycombinator.com/item?id=48624232)\n\nPoints: 1\n\n# Comments: 0", "url": "https://wpnews.pro/news/show-hn-baserates-dev-memorize-programmer-napkin-math", "canonical_source": "https://www.baserates.dev/", "published_at": "2026-06-22 00:50:48+00:00", "updated_at": "2026-06-22 01:10:50.676786+00:00", "lang": "en", "topics": ["developer-tools", "machine-learning"], "entities": ["Jeff Dean", "Simon Eskildsen", "InstantDB", "Claude", "Amazon"], "alternates": {"html": "https://wpnews.pro/news/show-hn-baserates-dev-memorize-programmer-napkin-math", "markdown": "https://wpnews.pro/news/show-hn-baserates-dev-memorize-programmer-napkin-math.md", "text": "https://wpnews.pro/news/show-hn-baserates-dev-memorize-programmer-napkin-math.txt", "jsonld": "https://wpnews.pro/news/show-hn-baserates-dev-memorize-programmer-napkin-math.jsonld"}}