https://johnseong.ca/blog Tech Lead | AI Systems en-us sandole97@gmail.com (John Seong) sandole97@gmail.com (John Seong) Sun, 16 Aug 2026 00:00:00 GMT https://johnseong.ca/blog/SystemDesignPrep https://johnseong.ca/blog/SystemDesignPrep I built and deployed a full system design interview prep app - 25 topic deep dives, 28 worked case studies with runnable MVP code, a back-of-envelope calculator, and flashcards - in a single Saturday afternoon. Here is the architecture bet that made it basically free to run, and the agent fan-out that made it fast to build. Sun, 16 Aug 2026 00:00:00 GMT sandole97@gmail.com (John Seong) developmentnextjssystem-designaiinterviews