Engineer III, Backend - Protection

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? 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 will you be doing? Own individual features end-to-end within the dispute automation buildout - deadline tracking, evidence collection, response templates by reason code Extend dispute lifecycle coverage to new PSPs, working from the existing pattern across the first five Build components of the native rules and signals engine - velocity rules, blocklists, device fingerprinting Contribute to the fraud vendor integration work (Riskified, Forter, Signifyd, Sift), improving how merchants compare and switch between providers Write RFCs and ADRs for the pieces you own, working mostly independently with light input from senior engineers Work closely with Product and your EM to turn a scoped piece of merchant pain into shipped automation Move across backend and, where needed, support the development of a new frontend Dispute Management dashboard What we're looking for Recent experience shipping production-ready software from scoping through to rollout—backend or full-stack—independently Comfortable writing RFCs and making architecture calls on your own projects with minimal senior oversight Comfortable transitioning into Python without prior experience Solid instincts on testing, observability, and security Nice to have, not required Exposure to card scheme rules, chargeback workflows, or fraud vendor integrations Experience with webhook-based event systems, rules engines, or orchestration platforms What you should know This team is new enough that some structure—on-call rotas, tooling, conventions—you'll be building it alongside doing the actual work Real ambiguity in the early days: you will be the one deciding what "good" looks like before anyone else has an opinion A handful of people today, so your individual output is highly visible ✅ A typical interview process An initial intro call with a Talent Partner An interview with the Hiring Manager Challenge Stage - Contextualised to the role A final, values-alignment interview What's the culture like at Primer? We're building a culture where people can do their best work and be proud of the impact they have. You'll be working with people who are mission-driven, smart, and reflective, and who are genuinely invested in building exceptional products and delivering success for our merchants. We work remotely, and have done since day one. We believe that building a successful, profitable company goes beyond proximity. We invest in our relationships through great remote working practices and thoughtfully designed face-to-face time, including workations, our annual company retreat, and access to co-working spaces across most major cities. The work is challenging. Scaleups are a challenge, and building category-defining products is a challenge. But there's a meaningful difference between a challenge and a struggle. At Primer, the right challenge comes with the right support: strong onboarding, a collaborative environment, and a team that is genuinely invested in your success. It's never something you face alone. Our benefits 🌍 We are fully remote and globally distributed; and have been since day one 💰 Competitive share options 🌴 Uncapped holiday, with 25 days minimum to be taken 🗣️ Co-working space access across major cities 📅 Workations & Company Retreat 💻 The best equipment for your role 🏠 £500 towards your home office setup 🔎 Generous learning budget 🏥 Private Medical Insurance 📈 A broad set of additional perks and benefits ( depending on location) Don’t meet every single requirement? At Primer, we're dedicated to building a diverse, inclusive, and authentic workplace. If you're excited about this role but your experience doesn't align perfectly with every qualification listed, we encourage you to apply. You may be the right candidate for this or other roles. Primer is committed to the equal treatment of all current and prospective employees and adopts a zero-tolerance approach to discrimination, regardless of age, disability, sex, sexual orientation, pregnancy and maternity, race or ethnicity, religion or belief, gender identity, marriage and civil partnership, or any other background or belief.