Senior Engineer, Backend - Protection

About 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.

About the Protection Team

We play a key role in helping merchants handle disputes and prevent fraud. The Protection team owns the risk management suite that surfaces these threats, and helps merchants build automation to handle them at scale.

What You Will Be Doing

• Move across the backend and, where needed, support development of our new dashboard frontend.
• Architect and build the automation merchants need to handle payment disputes at scale: notification, deadline tracking, evidence collection, responses.
• Expand our dispute coverage from five PSPs to the rest of Primer's network.
• Work directly with third-party fraud vendors (Riskified, Forter, Signifyd, Sift) to build a unified comparison and switching experience, rather than the current bolt-on integration.
• Design and ship native rules and signals engines like velocity rules, blocklists, and device fingerprinting as automation merchants configure directly.
• Make early architecture calls—service boundaries, integration patterns, data models—that decide how well this automation scales as more merchants and PSPs come online.
• Partner closely with the EM and Product to turn merchant pain into automation that ships.

What We're Looking For

• Experience owning backend systems end-to-end (design through shipping through monitoring), ideally in fraud, risk, payments, or another consequential space.
• Comfortable designing systems from scratch.
• Strong architecture and code-quality instincts.
• Experience mentoring or raising the technical bar for people around you.
• Proactive mindset focused on shipping early and often to drive work into customers' hands quickly.
• History of setting and maintaining a high bar for quality in shipping.

Nice to Have

• Exposure to card scheme rules, chargeback workflows, or fraud vendor integrations.
• Experience with webhook-based event systems, rules engines, or orchestration platforms.
• Willingness to pick up frontend work as needed.

Good to Know

• This team is new enough that you will be building structure alongside doing the actual work (on-call rotas, tooling, conventions).
• Expect real ambiguity in the early days: you will decide what "good" looks like.
• Highly visible role within a small, focused team.

Typical Interview Process

1. Initial intro call with a Talent Partner
2. Interview with the Hiring Manager
3. Challenge Stage (contextualized to the role)
4. Final values-alignment interview

Benefits & Perks

• Remote-First Culture: Fully remote work with access to co-working spaces in major cities.
• Equity: Competitive share options.
• Flexible Holiday: Minimum 25 days per year.
• Equipment & Home Office: The best equipment for your role plus £500 toward home office setup.
• Growth & Learning: Generous learning budget.
• Health: Private medical insurance.
• Events: Workations and an annual company retreat.