Senior Security Engineer

Primer.io · United Kingdomsenior

In short

▸Ingeniero de seguridad senior responsable de la seguridad de productos y aplicaciones en una plataforma de pagos a escala.
▸Trabajas de forma hands-on: revisiones de seguridad, modelado de amenazas, automatización y colaboración directa con equipos de ingeniería.
▸Eres el segundo ingeniero en una función de seguridad en crecimiento, con autonomía para definir tu propia hoja de ruta y tomar decisiones clave.

Clear communication in English with engineering teams is required.

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What they ask for

✓Experiencia real en seguridad de productos o aplicaciones (revisiones, modelado de amenazas).
✓Capacidad para leer, escribir y crear código y automatizaciones.
✓Juzgar riesgos con criterio: distinguir amenazas reales de teóricas.
✓Capacidad de planificar y entregar proyectos independientes con dirección clara.
✓Comunicación efectiva con ingenieros no especializados en seguridad.
✓Capacidad para manejar cambios constantes entre trabajo proactivo y operativo (BAU, auditorías, incidentes).

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CloudInfraProduct SecurityThreat ModellingSecurity ReviewsCompliance (SOC2, PCI)Penetration TestingAutomationToolingAppSec Roadmap

Who should you write to at Primer.io?

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An Introduction to Primer Primer is the unified infrastructure for global payments. We give finance and payments teams the visibility and control to reduce complexity, improve performance, and capture more revenue - all from a single platform. Backed by Sofina, Peak XV Partners, ICONIQ, Tencent, Accel, and Balderton, we're building the payments layer the world's best companies rely on. Watch our showcase > Read up on our $100m Series C Learn more about our culture > Which team will you be joining? You’ll be joining the ProdSec/AppSec team to help build the entire product security surface for a company processing payments at scale: threat modelling, security review, compliance, incident escalation, and the multi-year AppSec roadmap. You'd be the second hire, and the person that function finally gets to share the work with. This is a hands-on delivery role, and a genuinely formative one. You’ll help set the security strategy and architecture; you take real ownership of the work that turns it into reality, reviews, research, automation, and the day-to-day partnership with engineering teams. You'll have a clear direction to work within and someone senior to learn from, while still owning your projects end to end. Security at Primer sits close to the engineering teams it protects rather than off to one side, so you'll spend real time embedded with the people building Cloud, Infra, and product. For someone who wants to go deep in product security with room to grow, there are few better seats than being the second engineer in a function that's only now scaling. What will you be doing? Running security reviews and threat modelling on features and systems across Primer's product, and turning findings into clear, actionable guidance for the teams shipping them Independently planning and delivering your own security projects, from initial design through to rollout Building tooling and automation that makes future reviews faster and cheaper to run Coordinating penetration testing and tracking remediation through to closure Supporting the recurring compliance work (SOC2, PCI), including evidence collection and remediation tracking against fixed audit windows Contributing to AppSec roadmap initiatives across areas like application threats, AI security, supply chain security, and ASPM Picking up proactive security work, threat research and hands-on investigation, that a one-person function has never had the capacity for Working alongside Cloud, Infra, and GRC on the security aspects of their projects What we're looking for Working experience in product or application security: you've done security reviews or threat modelling and can spot the risks that matter The ability to read and write code, not just review it. You're comfortable building small tools and automation rather than only filing findings Sound judgement about risk. Nice to have: Exposure to compliance frameworks like SOC2 or PCI, or genuine appetite to learn them Background in payments, fintech, or another regulated, high-stakes domain Interest in areas like supply chain security, detection engineering, or AI security You may not like it here It's remote-first and high autonomy. You'll get direction, but nobody checks your progress daily. If you need close structure, this will be uncomfortable You'll move between proactive project work and reactive BAU, and priorities will shift as audits and incidents land. Tolerating that change is part of the role.

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