Staff Engineer, Machine Learning

We’re the world's first unified payment infrastructure, empowering businesses worldwide to unleash their payment potential. By choosing our platform, merchants can take control over their payment stack, create unique commerce experiences, accelerate their roadmap and increase payment success. We strive to make something complex incredibly simple and intuitive. The world's top investors, including Accel, Balderton, Iconiq, and Tencent, have invested in Primer's vision to rebuild payments and commerce from the ground up.

Join us in shaping the future of payments and commerce.

At Primer, we’re building the future of payments, and machine learning will play a central role in that journey. We’re looking for a hands-on Staff Machine Learning Engineer to build and scale our AI capabilities from the ground up.This is a high-impact opportunity to shape our approach to AI, lay strong foundations, and work at the intersection of engineering, data science, and product.

🔍 What You’ll Be Doing

• Own the end-to-end lifecycle of ML-powered features - from problem definition and data exploration to model training, deployment, and monitoring

• Help build the foundations and define the future of ML at Primer. where you’ll have influence from day one.

• Collaborate with product, data, engineering and platform teams to identify and prioritise impactful ML use cases

• Design and build core ML infrastructure including versioning, CI/CD, and observability tooling

• Work across teams and functions as a staff-level IC, acting as both an aggregator and technical leader

• Bring a pragmatic, impact-first mindset to experimentation and model evaluation

• Engage with customers to validate ideas and test new solutions - a chance to help shape real product outcomes

• Whether you see your path evolving toward technical leadership or people management, we’ll support your growth every step of the way

👀 What We’re Looking For

• 6+ years of experience in ML engineering, data science, or applied research

• Familiarity with payments or e-commerce - this is essential as you’ll be the domain expert from day one.

• Excellent Python programming skills and strong familiarity with ML libraries such as scikit-learn, XGBoost, TensorFlow, PyTorch, Keras etc.

• Proven track record deploying ML models to production (API, batch, or streaming contexts)

• Solid understanding of the modern software engineering, infrastructure and data technologies

• Experience working with LLMs, embeddings, or vector databases

• Comfortable operating in ambiguous, fast-paced environments

• Cloud experience (AWS preferred, but GCP or Azure is fine)

• You enjoy working in an office-setting, we are remote-first and always will be!

• You are not comfortable with shifting context and navigating ambiguity

• You don’t enjoy testing your code, we have no testers or QA’s here at Primer

We’re building a culture where people can come and do their best work and enjoy it. We want our people to be proud of the impact that they have at Primer, and of the work that they are doing. You will be working with a team of people who are mission-driven, smart, and reflective, and who are invested in building exceptional products and delivering success for our merchants (and we also know how to have fun along the way).

We work remotely. We believe that building a successful, profitable company goes beyond proximity. We invest in our relationships with each other through great remote working practices and thoughtfully designed face-to-face time together. Our heads-together time comes in the form of workations, our annual company retreat, and co-working space access worldwide.

Finally, let’s go ahead and say it. The work that we do is challenging. Startups are a challenge, building category defining products is a challenge. You should be prepared for a challenge at Primer. But, there’s a big difference between a challenge and a struggle. The key difference is that the right challenge comes with the right support structures, an acceptance that not everything always goes to plan, a collaborative environment, and a great team around you. It’s never a challenge that you will face alone.

• We are fully remote

• Competitive share options

• Uncapped holiday, with 25 days minimum to be taken

• Co-working space access

• Workations & company retreat

• The best equipment for your role

• £500 towards your home office setup

• Generous learning budget

• Medical insurance

• A broad set of additional perks and benefits (depending on location)

At Primer, we’re dedicated to building a diverse, inclusive, and authentic workplace. If you’re excited about this role but your past experience doesn’t align perfectly with every qualification in the job description, 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, regardless of background or beliefs—see our diversity commitment statement for more details

Primer adopts a zero-tolerance approach to discrimination.

We are committed to providing equal opportunities to all current and prospective employees regardless of age, disability, sex, sexual orientation, pregnancy and maternity, race or ethnicity, religion or belief, gender identity, or marriage and civil partnership.