Design a schema and defend it
By the end of today you can take a business description, produce a schema and an API for it, and defend every decision against someone actively looking for holes.
YesterdayDays 35 to 45 covered backend layers, FastAPI, validation, auth, sessions and tokens, security basics, schema design, SQL, indexes, transactions and ORMs.
TomorrowTomorrow begins Phase 5, and the question of what changes when real users depend on this.
Why this matters
Being able to defend a design under questioning is what separates knowing the concepts from being trusted with them. It is also exactly what a technical interview measures.
- Schema design
- Reviewing a design
- Tradeoff reasoning
- Defence in depth
Learn it
70 minCopy this into Claude or ChatGPT. It quizzes you before it explains anything, which is deliberate. The resources under it are how you check what it told you.
Today's Master Prompt
Free · sign inA prompt written for this day alone: your level, the exact scope, what to leave out, and an instruction to quiz you before it explains anything. Paste it into Claude or ChatGPT and it teaches you today's material.
Check it against something that is not a model
An assistant can be fluent and wrong, and on a topic you met today you will not catch it. These cover the same ground and were made by people who do this for a living, so they are what you hold the explanation up against. They are other people's work and we only link to them, so judge them for yourself.
3 hand-picked resources
Free · sign inVideos, official docs and articles covering the same ground, each opened and annotated by hand. They are what you check the assistant against on a day you cannot yet catch it being wrong.
Build it
55 minWrite up the ticketing design as you would hand it to a colleague: schema with keys and constraints, endpoint table with methods and status codes, where each authorization check lives, which indexes you would create and why, and a paragraph on the seat-holding race and how you resolve it. Then write the strongest argument against your own approach.
Recall it
25 minAnswer out loud, reveal, then mark honestly whether you had it. That score is the only thing on this page you do not get to choose.
5 recall questions
Free · sign inQuestions you answer from memory, then grade yourself against the real answer. The score is carried into the mastery rating below it, so an honest miss cannot quietly become a tick.
Rate it
Completion and mastery are tracked separately. Be honest, because an inflated rating only means the concept resurfaces sooner.
Mastery tracking
Free · sign inRate yourself against five named criteria per concept. Completion and mastery are tracked separately, and anything you rate shakily comes back automatically on a spaced schedule.
Recap
- 01A design is only as good as your answers to the attacks on it
- 02Concurrency problems need a named lock or atomic operation, not a vague transaction
- 03Authorization belongs where the data is loaded, not where the route is declared
- 04Knowing your own weakest decision is part of the design
Your progress
Free · sign inMark days complete, pick up where you left off across devices, and watch completion and mastery diverge. Free, and the account exists only so ninety days of work cannot vanish with a cleared browser.