Senior ML Engineer

Senior Machine Learning Engineer

Salary: £70,000–£90,000

Location: London (Hybrid)

The Opportunity

We're looking for a Senior Machine Learning Engineer to help design, build, and deliver next-generation AI systems. You will work across LLMs, retrieval-augmented generation (RAG), and modern agent frameworks to transform large, unstructured data into meaningful insights and production-ready capabilities.

This is a hands-on role within a growing AI team, offering the chance to shape architecture, build scalable pipelines, and ship features that directly impact users.

Responsibilities

  • Develop, integrate, and fine-tune LLMs for natural-language understanding, reasoning, and workflow automation.
  • Build agentic/LLM-driven workflows for multi-step decision making across diverse data sources.
  • Architect and deliver ML features such as pattern recognition, entity extraction, and intelligent automation.
  • Design scalable data and streaming pipelines capable of handling large, heterogeneous datasets.
  • Build and optimize vector search, embeddings, and RAG systems to support high-quality retrieval.
  • Deliver production-ready APIs, services, and model inference systems.
  • Manage deployment, monitoring, observability, and continual improvement of ML models.
  • Evaluate model performance using offline metrics, A/B tests, latency and cost optimisation.
  • Work closely with product and domain experts to translate requirements into robust ML solutions.

Who You Are

  • Strong proficiency in Python and experience with PyTorch or TensorFlow.
  • Practical experience with LangChain, LangGraph, AutoGen, or similar LLM/agent frameworks.
  • Skilled in prompt engineering, integrating foundation model APIs, and LLM fine-tuning techniques.
  • Expertise in building RAG systems, vector databases (e.g., Pinecone, Weaviate), and embedding pipelines.
  • Experience with ML/LLMOps for monitoring, evaluation, and traceability.
  • Solid understanding of distributed systems, microservices, and real-time data processing.
  • Comfortable with containerisation and cloud infrastructure (Docker, AWS, Terraform, etc.).
  • Experience deploying production AI systems with a strong focus on reliability and safety.
  • Background in NLP, information extraction, or large-scale unstructured data processing.
  • Experience in security, intelligence, or data-heavy platforms is a plus but not required.

Education & Experience

  • Degree in Computer Science, AI/ML, or equivalent practical experience.
  • Demonstrated experience building and shipping ML/AI products at scale.
  • Proven track record working with LLMs, RAG pipelines, or agent-based systems.

Work Environment

  • Hybrid: mix of remote work and in-person collaboration in our London office.
  • Flexible schedule within standard business hours.

Job Details

Company
Oscar
Location
Slough, Berkshire, UK
Hybrid / Remote Options
Employment Type
Full-time
Posted