70x Performance Improvement in Tax Import Services

Challenge

The tax import service was constrained by a single-threaded AWS Lambda process, which serialized requests and caused significant delays when processing large or complex data sets. This bottleneck not only slowed down performance but also created scalability risks as customer data volumes grew.

Leadership

I collaborated closely with engineering to re-architect the service, shifting from a single-threaded Lambda approach to a multi-threaded method capable of handling concurrent processes. To safeguard stability and ensure uninterrupted service, we also implemented a polling mechanism that validated process completion without overloading the system. Throughout the redesign, I balanced product priorities with technical tradeoffs, ensuring that performance gains didn’t come at the cost of reliability.

Outcome

The new architecture delivered a 70x performance boost, reducing imports from minutes to near-instant execution. This improvement not only transformed user productivity but also established a scalable foundation for future growth, proving the platform could handle enterprise-level tax workloads with speed and resilience.