Senior ML Engineer - Build Production ML, Remote + Equity

primer.io; United Kingdom; Remote; GBP 90,000 - 120,000; Full time

Benefits offered by this job

Remote-first culture

Uncapped holiday (25 days minimum)

£500 home office setup

Job summary

Primer is building an ML-first culture for global payments. You will be our first Senior ML Engineer, partnering with the Staff Engineer to shape ML foundations and tooling across product, data and engineering.

You will own the end‑to‑end ML lifecycle, productionise routing decisions, and mentor peers while collaborating with stakeholders to validate ideas against real usage and metrics.

Qualifications

• Senior experience in ML engineering, data science, or applied research with production deployments.
• Ability to design and run experiments and A/B tests and report results.
• Strong Python skills with ML libraries such as scikit-learn, XGBoost, TensorFlow, PyTorch or Keras.
• Solid grounding in modern software engineering, infrastructure and data tooling, including MLOps challenges across the full ML lifecycle.
• Familiarity with reinforcement learning and its applications in practice.
• Cloud experience (AWS preferred; GCP or Azure also acceptable).
• Exposure to payments or e-commerce is a plus, not a prerequisite.

Responsibilities

• Own the full lifecycle of ML-powered features from research to deployment and monitoring in production.
• Productionise ML-driven decisions across the payment flow and build supporting infrastructure (versioning, CI/CD, observability).
• Collaborate with product, data and engineering to ship measurable ML outcomes.
• Balance experimentation with practical, impact-first approaches; avoid over-engineering.
• Mentor engineers in ML techniques and tradeoffs, promoting simplicity where appropriate.
• Engage with customers to validate ideas against real usage and feedback.
• Help set technical direction and prioritise use cases worth pursuing for reliability.

Skills

ML engineering

Python

Experimentation

A/B testing

Reinforcement learning

Education

Senior level experience

Tools

scikit-learn

XGBoost

TensorFlow

PyTorch

Keras

Job description

Primer is building an ML-first culture for global payments. You will be our first Senior ML Engineer, partnering with the Staff Engineer to shape ML foundations and tooling across product, data and engineering.

You will own the end‑to‑end ML lifecycle, productionise routing decisions, and mentor peers while collaborating with stakeholders to validate ideas against real usage and metrics.