Senior Backend Engineer — Payments & PCI Compliance

About the role: We run a payment gateway that processes live card transactions for merchants, and we're investing seriously in the security, compliance, and architecture of our platform. We're hiring a senior backend engineer to own that work end-to-end — to take our Spring Boot payment stack and make it secure, PCI-validated, and clean to integrate with. This is a high-ownership role, not a ticket queue. You'll be trusted to assess what needs to be done, prioritise it, and drive it to completion — coordinating with our acquirer, QSA, and scanning vendors as you go. If you enjoy turning high-stakes, ambiguous payment problems into well-engineered, auditable systems, you'll fit right in. What you'll do: Drive our PCI DSS v4.0.1 validation as a service provider — scope definition, remediation, the SAQ/assessment process, and keeping us compliant year-round. Harden how we store, process, and transmit cardholder data: encryption, tokenization, masking, and disciplined logging hygiene. Desi...