Senior Engineer - 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?

• 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 the native rules and signals engine like velocity rules, blocklists, device fingerprinting, as automation merchants configure directly

• Make early architecture calls - service boundaries, integration patterns, data model, 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 (invisible disputes, missed fraud signals) into automation that ships, not just tickets

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 and looking to ship early and often—you drive work into customers' hands quickly rather than polishing indefinitely

• History of setting and maintaining a high bar for quality in shipping—missing disputes because of bugs costs our customers real money

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

• Willingness to pick up frontend work as needed

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
🌴 Flexible 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.