← Engineering Logs

Tag

#backend

4 articles

  1. The Discount That Knew You Were Hesitating: Rule-Based Personalisation in an Online Pharmacy

    How Zovita+ turns browsing into personal discounts without a machine-learning model: one visitor key for guests and customers, interaction counters, six offer rules, one pricing function for the bag and the charge, offers locked and redeemed once at checkout, guest-to-account merging, A/B tests, and the edge cases that shaped it.

    10 minThe Engineering Logs

  2. One Seat, Two Buyers: Race Conditions, IDOR and Keys in a Cinema Booking System

    How BookMyMovie makes sure one cinema seat is never sold twice, a guessed booking number shows nothing, and a leaked or missing key can't quietly break tickets: row locks, lock order, a NULL-tolerant unique key, status compare-and-set, idempotency, IDOR scoping, HMAC tickets, captcha step-up, and the bugs that still got through.

    11 minThe Engineering Logs

  3. The Last Mango Problem: Race Conditions in a Real Marketplace

    What happens when fifty people try to buy the last item, use a single-use coupon or book a nearly full pickup window at the same instant, the MySQL snapshot detail that almost overbooked a stall, and the quieter races that hide in stock forms, restocks and payments.

    10 minThe Engineering Logs

  4. Is Node.js Still Enough? When to Move Your Backend to Rust

    Is Node.js failing you, or are you outgrowing it? A realistic look at event loop limits, CPU bottlenecks, and when to pragmatically migrate to Rust.

    9 minBattle of BackFrontFirst on DEV