Software Engineer III, Backend - Protection
- Level
- Senior
Not stated in the posting: salary, work type, visa.
Open. First seen 10 August 2026.
About the role
Primer.io's standard text
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
Primer.io's standard text
✅ 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?
Primer.io's standard text
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.
Primer.io's standard text
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)
Primer.io's standard text
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.
What this role asks for
In most of Primer.io's ads
Python
Named in most of its open postings, whatever the role.
61% of this description is written for the role. The rest is Primer.io's standard text, folded away below.
Compared with Primer.io's other open jobs.
The team: Engineering HIRES STEADILY
This role is one of 8 open in Engineering. 6 were posted in the last 30 days and the oldest in August: a team that hires all year rather than one being built.
WHAT THE TEAM WORKS WITH, ACROSS ITS POSTINGS
Python (6 of 8), AWS (4 of 8), CI/CD (3 of 8), GCP (3 of 8), Azure (2 of 8), Golang (2 of 8), Keras (2 of 8)
OTHER ROLES ON THIS TEAM
- Senior DevEx Engineer - Infrastructure posted Sep 30
- Software Engineer III, Frontend - Account Experience posted Sep 28
- Senior Engineer, Fullstack - Growth posted Sep 28
- Senior Engineer, Backend - Orchestration posted Sep 28
- Senior Machine Learning Engineer posted Sep 24
- Senior ML Engineer posted Sep 24
- Staff Engineer, Frontend posted Aug 10
From the team and dates on Primer.io's own job board.
Similar jobs
- Senior Machine Learning Engineer at Primer.io
Also at this company - Senior ML Engineer at Primer.io
Also at this company - Senior Solutions Engineer at Primer.io
Also at this company - Solutions Engineer at Primer.io
Also at this company - Security Engineer III - Security Operations at Primer.io
Also at this company - Staff Engineer, Frontend at Primer.io
Also at this company
Is this your posting? Email info@careerholo.com to have it removed.