Car rental at scale — availability that never lies
Braganza is a full-stack car rental platform: customers browse a live fleet, pick dates, price a booking and pay, while operators manage vehicles, pricing rules and handovers from an admin side.
The hard requirement was consistency. A car shown as available must actually be bookable, and two people hitting checkout on the same vehicle at the same second must not both succeed.
Availability checks and booking creation run inside a single transaction with row-level locking on the vehicle, so concurrent checkouts serialise instead of racing. The loser gets a clean conflict response, not a corrupted booking.
Date-range availability across the whole fleet is expensive to compute per request, so results are cached in Redis keyed by fleet segment and window, and invalidated precisely when a booking touches that window rather than flushed wholesale.
Seasonal rates, durations and add-ons all stack. Pricing lives in a rule table evaluated in a deterministic order, which keeps quotes reproducible and auditable long after the booking is made.
The price a customer sees while picking dates has to match what the API charges at checkout. Pricing is computed server-side and the Next.js front-end renders only what the API returns, so there is no second implementation to drift.