Senior AI Engineer: Data & Models (Hybrid—London/Paris)

Dex; Greater London; Hybrid; GBP 110,000 - 180,000; Full time

Job summary

Dex is seeking a Member of Technical Staff to own research-engineering tasks across data curation, model fine-tuning, and agent execution harnesses. You will apply SFT and RL, evaluate rigorously, and turn prototypes into hardened systems.

You will work hybrid from London or Paris, collaborating with software and curriculum teams to design scalable training pipelines and robust evaluation frameworks.

Qualifications

• Hands-on experience fine-tuning or post-training models using SFT or RL.
• Deep AI/ML fundamentals: model optimisation, RLHF, evaluation design.
• Strong Python and production-grade code discipline.
• Ability to break down ambiguous research questions and drive multi-month initiatives.
• Based in or willing to work hybrid from London or Paris.

Responsibilities

• Design, curate, and scale training-data pipelines for agent training.
• Fine-tune and post-train models with SFT/RL and evaluation suites.
• Develop and harden agent harnesses and sandboxed execution environments.
• Translate open-ended AI questions into technical plans and production-ready systems.
• Drive technical decisions across the team without relying on line-management.

Skills

Fine-tuning models

AI/ML fundamentals

Python programming

Break down AI problems

Hybrid London/Paris

Job description

Dex is seeking a Member of Technical Staff to own research-engineering tasks across data curation, model fine-tuning, and agent execution harnesses. You will apply SFT and RL, evaluate rigorously, and turn prototypes into hardened systems.

You will work hybrid from London or Paris, collaborating with software and curriculum teams to design scalable training pipelines and robust evaluation frameworks.