Principal .NET Software Engineer - Cloud Payments Platform

Significant experience (typically 10+ years) of professional engineering with expert proficiency in C#, .NET, and SQL. · Deep experience in payments: online payments, EMV device-based transactions, digital wallets (e.g., Apple Pay, Google Pay), PayFac/orchestration flows, bank account rails (ACH/EFT), and international/multi-currency payment flows.

Proven ability to modernize production financial systems into cloud-native, distributed architectures

Familiarity with monitoring and observing distributed systems using modern observability tooling

Proven ability to work cross-functionally with Product, Security, Compliance, and Operations, and to represent engineering effectively to non-technical stakeholders

Experience using AI-assisted development tools to enhance productivity and code quality

Deep hands-on experience with several of the following:

ISO 8583 transaction messaging

ISO 20022 data models and payment messaging

DUKPT key-management and secure device cryptography

Hardware Security Modules (HSMs) and secure key lifecycle

EMV payment kernels and card/device authentication flows

Strong knowledge of:

Modern API and integration design (RESTful services), asynchronous messaging/queueing, caching, event-driven architecture, high-availability patterns

AWS or Azure, containerization, orchestration, and CI/CD automation

PCI-DSS, encryption, tokenization, key-rotation, and secure coding principles

Nice to Haves:

Experience with multi-region cloud architecture and distributed data patterns

Experience with modern UX/front-end development (e.g., JavaScript/TypeScript)