Research Engineer, Machine Learning (Reinforcement Learning)

Company: Humanloop
Apply for the Research Engineer, Machine Learning (Reinforcement Learning)
Location: London
Job Description:

Overview

In this role you will co-develop reinforcement learning capabilities for large language models, balancing research exploration with robust engineering. You’ll help build scalable RL infrastructure, create test environments, and push model reasoning and tool-use capabilities. You work closely with researchers and engineers to advance safe, impactful AI systems at scale. This position offers opportunities to shape next-gen models and contribute to Anthropic’s mission of trustworthy AI.

Pay / Benefits

  • Competitive compensation and benefits
  • Optional equity donation matching
  • Generous vacation and parental leave
  • Flexible working hours
  • Lovely office space for collaboration

Responsibilities

  • Architect and optimize core RL infrastructure, including training abstractions and distributed experiment management across GPU clusters
  • Scale systems to support increasingly complex research workflows
  • Design and implement novel training environments and evaluation methodologies for RL agents
  • Improve stack performance via profiling, optimization, and benchmarking
  • Develop efficient caching and debugging for distributed training and evaluation
  • Collaborate across research and engineering to build automated testing frameworks and scalable APIs

Key requirements

  • Proficient in Python and async/concurrent programming (e.g., Trio)
  • Experience with ML frameworks (PyTorch, TensorFlow, JAX)
  • Industry experience in machine learning research
  • Ability to balance research exploration with engineering implementation
  • Enjoys pair programming and collaborative work
  • Strong code quality, testing, and performance mindset
  • Solid systems design and communication skills
  • Passion for AI safety and beneficial AI
  • Collaboration
  • Communication
  • Problem-solving
  • Python
  • async/concurrent programming (Trio)
  • PyTorch

…

Posted: October 1st, 2026