Senior ML Engineer — Remote, Production ML for Payments

Primer API Limited; United Kingdom; Remote; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Private Medical Insurance

Home office stipend

Remote-first culture

Co-working space access

Workations & Company Retreat

Learning budget

Job summary

Primer API Limited is hiring a Senior ML Engineer to help build the ML foundations from the ground up. You’ll be the first in this team alongside the Staff Engineer, shaping the ML roadmap and working with engineering, data and product to deploy production ML in payments.

You’ll own end-to-end ML features, productionise routing decisions, and mentor others while collaborating with customers to validate ideas and set technical direction.

Qualifications

• Senior ML engineering, data science, or applied research with production deployments.
• Ability to design and run experiments and A/B tests with clear results.
• Strong Python and ML library experience (scikit-learn, XGBoost, TensorFlow, PyTorch, Keras).
• Solid grounding in software engineering, infrastructure and data tooling with ML lifecycle awareness.
• Familiarity with reinforcement learning concepts and practical relevance.
• Cloud experience — AWS preferred; GCP/Azure acceptable.
• Payments/e‑commerce exposure is a plus.
• Comfort working autonomously in ambiguous environments.

Responsibilities

• Own the full lifecycle of ML-powered features from research to production.
• Productionise routing decisions and build ML infra (versioning, CI/CD, observability).
• Collaborate with product, data, and engineering to ship measurable outcomes.
• Balance pragmatic experimentation with simple, effective approaches.
• Mentor engineers on ML techniques and tradeoffs.
• Engage with customers to validate ideas against real usage.
• Help set technical direction and prioritize use cases.
• Establish patterns for reliable, repeatable ML at Primer.

Skills

ML engineering

Data science

Python

ML libraries

MLOps

Experiment design

Reinforcement learning

AWS

Tools

CI/CD

Observability

Versioning

Cloud tooling

Job description

Primer API Limited is hiring a Senior ML Engineer to help build the ML foundations from the ground up. You’ll be the first in this team alongside the Staff Engineer, shaping the ML roadmap and working with engineering, data and product to deploy production ML in payments.

You’ll own end-to-end ML features, productionise routing decisions, and mentor others while collaborating with customers to validate ideas and set technical direction.