Kastanie

Kastanie lets a workshop publish its free slots, take bookings with the bike and the fault attached, and move each job through check-in, repair and pickup. I lead the booking core: the slot engine, the calendar sync and the notification pipeline.

Built on Next.js with Postgres behind Prisma, deployed on AWS through Terraform. The part I am proudest of is the double-booking guard: an advisory lock per workshop and day that has held through two Saturday peaks without a single collision.