Senior Machine Learning Engineer | Python, PyTorch, JAX | Fully remote, UK
£95,000 to £120,000. Permanent.
London. Fully remote across the UK.
This is for an ML engineer who has already learned the uncomfortable bit: a model that works in a notebook is only the start. You will own core ML systems from data and training through to inference and how they behave in production.
Our client is an early-stage AI product company building applications that get on with everyday tasks before you ask. A prototype exists, launch is ahead, and the company is funded without relying on an upcoming round.
You'll work in a small, distributed technical team. The role is hands-on and the work is yours to own, with close links to research, product and engineering. You'll also review and mentor other ML engineers, mostly through the quality of your own technical decisions.
The trade-offs are real. Accuracy matters, but so do latency, cost, reliability and safety. Production failures are part of the work, and you'll be expected to trace them through models, data and systems instead of treating them as somebody else's problem.
The job
ML systems. Build the core machine learning systems for a long-horizon AI product. You'll take work from data preparation through training, evaluation, inference and iteration.
Production. Turn research ideas into systems that can serve real users. You'll investigate model failures and system issues from production signals, then ship changes and measure whether they worked.
Engineering. Write production-quality Python and work with PyTorch or JAX on GPU-based training and inference. Training, inference and data pipelines need to keep working, and stay maintainable, as the product changes.
Technical judgement. Own ambiguous problems without waiting for a detailed specification. Review work from other ML engineers and help raise the engineering standard through practical decisions, not process for its own sake.
What you'll bring
Essential:
- ML systems you have built and shipped to real users.
- Production-quality Python used for machine learning systems.
- PyTorch or JAX used beyond isolated experiments.
- Ownership across data, training, evaluation and inference.
- Production model failures you have investigated from real signals.
- Work balancing model quality against latency, reliability or cost.
- Other ML engineers whose work you have reviewed or who you have mentored.
- Existing right to work in the UK.
Useful: GPU training systems, inference optimisation, synthetic data, long-horizon models.
Who this suits
You are probably a Senior Machine Learning Engineer, Senior AI Engineer or experienced ML Engineer who prefers building and running systems to presenting research. You can take a vague problem and get it safely into production.
It won't suit you if you'd rather hand a model over once the evaluation looks good. Here you stay with it through inference, real users and whatever fails afterwards.
Let's talk
Actively looking or just curious, We welcome applicants from every background and will support reasonable adjustments.
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Senior Machine Learning Engineer in City of London employer: Xist4 IT Limited.
As a Frontend Engineer at our innovative company, you'll be part of a dynamic team dedicated to creating AI-native productivity applications that redefine everyday tasks. We offer a fully remote work environment, fostering a collaborative culture where your contributions directly impact product development. With opportunities for professional growth and the chance to work on complex, engaging projects, we are committed to supporting your career while ensuring a rewarding and meaningful work experience.
