Travel eSIM platform
A paid order has to become a working eSIM, every time, across two systems that can both fail.
The problem
Between a traveller paying and a working data profile arriving on their phone sit two independent third parties: the payment provider and the eSIM supplier. Either can time out, deliver a callback twice, or succeed slowly. A customer who has paid and then landed abroad with no connection is the one failure this business cannot absorb.
What I built
Provisioning runs as an idempotent job with a uniqueness lock, triggered only by a confirmed payment event and never by the checkout page. Suppliers sit behind a single driver interface, so adding a second one is a new class rather than a rewrite. A scheduled reconciliation pass sweeps for paid-but-undelivered orders as a safety net. Arabic is the primary language, so the storefront and the mobile app are built right-to-left first.
Where it landed
Duplicate webhooks and retries cannot double-provision or quietly drop an order, and a supplier can be replaced without touching checkout.