Tax computation on cloud transactions worldwide happens at the line-item level — far finer-grained and higher-throughput than invoice-level processing. In this domain, a miscalculation isn't a cosmetic bug; it has direct monetary consequences for customers and the business. The infrastructure underneath it has to be built to be right.
As one of the engineers owning this platform's foundation, I architected its infrastructure end to end: the Infrastructure-as-Code and CI/CD foundation, DNS and hosted-zone architecture per environment stage, VPC-based integration with internal services, and TLS termination at the load balancer. This was foundational work built from the ground up, so early decisions here shaped how the rest of the team could build on top of it.
In a financial system, "just retry" is not a safe default — a duplicate request after a network blip or timeout could mean double-charging or double-computing tax. I designed idempotency guarantees directly into the platform's API so that retries are always safe, regardless of what failed partway through.