Systems Engineer: AI Security & Infra

Refractal; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

UK Skilled Worker sponsorship

London-based in-person culture

Job summary

Refractal is hiring a Systems Engineer to own the services and infrastructure that keep our security platform secure in production. You will work across enforcement runtime, data integrity, tenant isolation, agent tracing, model services and cloud infrastructure.

You will turn security and operational requirements into measurable, testable systems and help set technical direction, engineering standards and roadmaps.

Qualifications

• Strong experience with backend, distributed or infrastructure systems. Python preferred.
• Production observability and distributed tracing experience.
• Experience building and testing responsive services under load.
• Relational databases and multi-tenant data experience (Postgres, RLS, migrations, access-control tests).
• Containers, cloud infrastructure and CD; experience with GCP, Cloud Run, Cloud SQL preferred.
• Solid understanding of operational security: least privilege, secret management, hardened containers, trust boundaries.
• Experience with UX design and Product Management is preferred.

Responsibilities

• Build and operate the runtime enforcement pipeline with low latency decisions.
• Own observability and agent tracing across the platform with useful traces, logs, metrics, alerts.
• Create tamper-evident evidence store and audit ledger for verifiability.
• Enforce multi-tenant isolation across services and data paths with RLS and tests.
• Build infrastructure for red-team and evaluation jobs with safe subprocess management.
• Develop reliable event and streaming services handling backpressure, retries, and disconnections.
• Operate model-serving services including detector artefacts, provider routing and GPU workloads.
• Own cloud infrastructure and CD, including Cloud Run, Cloud SQL, IAM and Secret Manager checks.
• Threat-model the infrastructure; protect secrets and define trust boundaries.
• Oversee Product Management of software dashboard, including UX decisions.

Skills

Backend systems

Distributed infra

Python

Observability

Distributed tracing

Load testing

PostgreSQL

Row-Level Security

Multi-tenant

Containers

Cloud infrastructure

GCP

Cloud Run

Cloud SQL

Operational security

UX design

Product management

Job description

Refractal is hiring a Systems Engineer to own the services and infrastructure that keep our security platform secure in production. You will work across enforcement runtime, data integrity, tenant isolation, agent tracing, model services and cloud infrastructure.

You will turn security and operational requirements into measurable, testable systems and help set technical direction, engineering standards and roadmaps.