Engineering
Engineering write-ups — page 3
Page 3 of 3.
- PlatformReceiving webhooks you don't control the shape ofBuilding an endpoint that consumes cohort events from one vendor and pushes segments into another — multiple payload shapes, idempotency, retries with backoff, and durable sync state.
- SecurityThe endpoint that sends an SMS to anyone who asksAny unauthenticated endpoint that triggers a real-world action is an abuse vector. Layered rate limiting, a challenge, and the tracking you need to enforce either.
- PlatformPagination breaks the moment you reorder page onePinning admins and the current user to the top of a member list sounds trivial. It quietly guarantees duplicates and omissions on every page after it.
- AI systemsAsking a model to score a match, and storing the reasonsGenerating a 0–100 relevance score for an application, with the specific evidence behind it — why the explanation matters more than the number, and where scoring quietly goes wrong.
- PlatformEvery unfollow is a delete you have to rememberBuilding a fan-out-on-write timeline where each user's feed is materialised rows in a table — and why the hard part is not writing them, it's removing them when the social graph changes.