Staff Engineer – LLM‑Driven Evolutionary Optimisation

AI Startups UK; Greater London; Hybrid; GBP 110,000 - 150,000; Full time

Benefits offered by this job

Equity & Ownership

Private healthcare

Visa sponsorship

Relocation benefits

London office (in-person work)

Job summary

Callosum is building the next generation of AI systems in London, delivering an LLM-guided search loop that evolves programs across kernels, runtimes, and policies. You’ll own the evolution loop, improve search quality, and extend the system to new verification domains.

You’ll collaborate across hardware, software and ML teams, turning experiments into scalable, reliable tools while advancing optimisation methods for heterogeneous workloads.

Qualifications

• Strong foundations in optimisation and search, including non-gradient-based methods.
• Ability to reason about exploration vs exploitation and objective design.
• Evidence of turning experimental systems into reliable software.

Responsibilities

• Develop the core program evolution loop, improving candidate generation and evaluation.
• Design search strategies balancing exploration and exploitation across large spaces.
• Build benchmarks to measure performance and stability of the optimiser.
• Turn the system into scalable internal infrastructure for new domains.

Skills

Optimization

Search algorithms

Engineering practice

LLM systems

Python

PyTorch

Tools

Python

PyTorch

Job description

Callosum is building the next generation of AI systems in London, delivering an LLM-guided search loop that evolves programs across kernels, runtimes, and policies. You’ll own the evolution loop, improve search quality, and extend the system to new verification domains.

You’ll collaborate across hardware, software and ML teams, turning experiments into scalable, reliable tools while advancing optimisation methods for heterogeneous workloads.