Staff Software Engineer

Location: Belfast (Hybrid)

The Mission

Own and evolve a high-throughput, security-critical payment gateway platform that processes real financial transactions at scale.

You won’t just ship features. You’ll shape architecture, raise engineering standards, and solve cross-cutting problems that impact reliability, compliance, and performance across the platform.

What You’ll Own

🔹 Architecture & Technical Direction

• Define and evolve gateway architecture across multiple services

• Lead design of secure, high-availability transaction systems

• Drive decisions across authentication, transaction routing, and merchant services

• Balance scalability, performance, compliance, and maintainability

• Identify and reduce systemic technical debt

🔹 Security & Compliance Leadership

• Own alignment with PCI DSS 4.0 requirements

• Champion secure-by-design and OWASP standards

• Lead threat modelling and secure design reviews

• Drive vulnerability remediation strategy and prioritisation

• Set authentication and session management standards (MFA, tokenisation, secure cookies, CSP controls)

🔹 Engineering Standards

• Define expectations for TDD / BDD and automated test coverage

• Establish CI/CD quality gates and release confidence standards

• Raise the bar on code review and technical documentation

• Improve observability and production monitoring practices

• Lead reliability and incident reduction initiatives

🔹 Cross-Team Influence

• Act as escalation point for complex architectural decisions

• Mentor Senior Engineers and grow technical leadership capability

• Influence roadmap feasibility with Product and Security

• Shape estimation and planning at programme level

• Communicate technical trade-offs clearly to senior stakeholders

What You Bring

Experience

• 8+ years backend software engineering

• Proven experience designing distributed, secure systems

• Experience operating in regulated or compliance-heavy environments

• Demonstrated cross-team technical leadership

Technical Depth

• Strong C# / .NET backend expertise

• Deep understanding of high-volume transactional databases

• Strong understanding of authentication and secure session design

• Experience designing for high availability and fault tolerance

• Strong production troubleshooting capability

How You Think

• Systems over services

• Long-term platform health over short-term fixes

• Security as a default, not a layer

• Influence through clarity, not authority

• Ownership without ego

What Success Looks Like

• Clear architectural direction across the gateway platform

• Measurable improvements in reliability and resilience

• Reduced security risk and faster remediation cycles

• Fewer production incidents, faster recovery

• Stronger senior engineers emerging under your mentorship