Lead Site Reliability Engineer

Our Purpose Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we’re helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential. Title and Summary Lead Site Reliability Engineer Overview We are seeking a Lead Site Reliability Engineer (SRE) with deep expertise in HP NonStop (Tandem) platforms and strong Payments Network / Transaction Switching knowledge to ensure the reliability, resilience, and scalability of Mastercard’s mission‑critical payment processing platforms. This role is responsible for end‑to‑end service reliability—owning availability, incident response, automation, release readiness, and operational excellence for real‑time, globally distributed payment systems processing transactions at massive scale. As a Lead SRE, you will set reliability standards, mentor engineers, and partner closely with engineering, infrastructure, and security teams to continuously reduce operational risk and improve platform stability. Key Responsibilities Service Reliability & Availability · Own availability, performance, latency, and resilience of payment platforms running on HP NonStop (Tandem) infrastructure · Define and enforce SLOs, SLIs, and error budgets for mission‑critical payment services · Proactively identify reliability risks and drive corrective and preventive actions Incident Leadership & Response · Act as a lead incident commander for high‑severity production incidents · Drive rapid triage, mitigation, and resolution across application, platform, and infrastructure layers · Lead blameless post‑incident reviews, ensuring strong root‑cause analysis and measurable follow‑ups Platform Engineering & Automation · Reduce toil by driving automation across monitoring, diagnostics, deployment, and recovery workflows on HP NonStop platforms · Partner with engineering teams to improve operability, observability, and failure handling · Support modernisation initiatives while ensuring PCI, security, and compliance requirements are met Release, Change & Resilience Engineering · Lead release readiness and production validation for changes impacting payment switching platforms · Define rollback, failover, and recovery strategies to minimise customer impact · Own participation in DR testing, BCP exercises, and site‑resilience planning for Payment Networks Payments Domain Ownership · Ensure deep operational understanding of payments transaction flows, including: o Single Message / Real‑time transaction switching o Debit, ATM, POS, and network routing behaviour · Partner with product and engineering teams to ensure reliability considerations are embedded early in design Leadership & Mentorship · Provide technical leadership and mentoring to SREs and operations engineers · Set standards for runbooks, monitoring quality, alert hygiene, and operational excellence · Influence reliability strategy and priorities at a programme and domain level Required Skills & Experience Technical Expertise (Must‑Have) · Strong, hands‑on experience with HP NonStop (Tandem) platforms · Deep knowledge of NonStop OS, Pathway, TMF, EMS, OSS, TACL, and diagnostic tooling · Experience supporting high‑throughput, low‑latency, real‑time transaction systems · Proven ownership of production reliability in 24x7 environments Payments & Domain Knowledge · Solid experience in payments networks or financial transaction processing · Understanding of transaction switching, routing, authorisation, and se