Solve hard problems where AI meets cybersecurity.

Open roles

AI Engineer

Engineering In person London £80k–£130k + equity

The role

Join as one of the first engineering hires after the technical co-founder. You will own core parts of the platform from day one: agent classification, runtime evidence pipelines, and policy enforcement across models and modalities.

This is a high-autonomy role with direct customer impact and a path towards leading the engineering organisation as we scale.

What we offer

  • Competitive salary, meaningful founding equity, and a performance-linked bonus.
  • Direct influence over the product, research agenda, and company direction.
  • Real, high-consequence AI deployments rather than purely synthetic environments.
  • London-based, in-person work, with UK Skilled Worker visa sponsorship and support for Global Talent applications.

What you'll work on

  • Build the runtime classification stack that decides whether an agent's proposed action is authorised before it executes.
  • Design action-boundary controls that allow, block, or redact sensitive data from flagged actions.
  • Build evidence pipelines that record every AI action, verdict, and rationale.
  • Compile natural-language company policies and regulation into executable runtime controls.
  • Develop multimodal ingestion and detection across models, tools, and data types.
  • Own systems end to end and ship them into real, high-consequence customer deployments.

What we're looking for

A technically exceptional builder who cares about getting AI safety and security right, and who grounds research in real-world impact.

  • Typically 0-3 years of post-university experience building AI or machine learning systems.
  • A strong foundation in computer science, machine learning, cybersecurity, or a related field.
  • Evidence of exceptional building ability through production systems, research at a leading lab, startup work, or open source.
  • A rigorous understanding of how AI systems fail and how adversaries can exploit them.
  • The ability to move quickly, communicate clearly, and own complex technical problems independently.

How to apply

Complete the application form with your CV and a short note about the most interesting system you have broken, built, or studied. Links to research, write-ups, and open-source work are strongly encouraged. Our process is an intro call, a technical deep-dive, a short practical exercise, and an offer, typically within two weeks.

Apply now

AI Red Team Engineer

Security research In person London £70k–£120k + equity

The role

Be Refractal's first dedicated AI security hire. Break agentic systems before adversaries do, then turn what you learn into repeatable evaluations, customer insights, and production security controls.

You will work across security research, offensive engineering, and product development, directly with the founders and our earliest customers.

What we offer

  • Competitive salary, meaningful founding equity, and a performance-linked bonus.
  • Direct influence over the product, research agenda, and company direction.
  • The opportunity to establish Refractal's security research function and grow into technical leadership.
  • London-based, in-person work, with UK Skilled Worker visa sponsorship and support for Global Talent applications.

What you'll work on

  • Red-team production and pre-production agents across browser, code, enterprise, and multi-agent environments.
  • Discover attacks involving prompt injection, goal manipulation, memory poisoning, tool abuse, identity, and data exfiltration.
  • Develop realistic exploit chains across model, application, identity, tool, and infrastructure layers.
  • Build automated attack agents, evaluation harnesses, and reusable security test suites.
  • Turn research findings into detections, runtime evidence, policy controls, and product requirements.
  • Assess customer deployments and communicate technically rigorous, actionable findings.

What we're looking for

An adversarial thinker with a builder's instinct who can move from an ambiguous attack hypothesis to a reproducible proof of concept.

  • A strong foundation in security, computer science, machine learning, or a related field.
  • Hands-on experience in offensive, application, cloud, product, or AI security.
  • The ability to build security tooling and proof-of-concept exploits, ideally in Python and a systems language.
  • Practical knowledge of modern agent architectures, including tool calling, retrieval, memory, orchestration, and permissions.
  • Strong experimental discipline, clear communication, and ownership of technically ambiguous problems.

How to apply

Complete the application form with your CV and a short note about the most interesting system you have broken, built, or studied. Links to research, write-ups, open-source work, CTF profiles, or working exploits are strongly encouraged. Our process is an intro call, a technical deep-dive, a short practical exercise, and an offer, typically within two weeks.

Apply now