Platform Engineer — AI Security Platform (London)

REFRACTAL; Greater London; On-site; GBP 110,000 - 150,000; Full time

Benefits offered by this job

UK Skilled Worker visa sponsorship

Job summary

Refractal, a London-based AI security company, seeks a product-minded platform engineer to own the core platform APIs, SDKs, and multi-tenant services. You will work with the founders to translate operational security needs into reliable interfaces and operator tools.

You will design authentication, API keys, session handling, and real-time data interfaces while ensuring robust testing, deployment, and customer integration across Cloud Run and related services.

Qualifications

• Strong backend experience with HTTP APIs and Python/FastAPI.
• Experience with observability, tracing, relational databases and migrations.
• Sound judgment on API design, versioning, SDKs, and compatibility.
• Solid understanding of authentication, authorisation, API keys and multi-tenant access control.
• Good JavaScript and React skills for operator-facing surfaces.
• Ability to work independently and own ambiguous customer problems.

Responsibilities

• Own stable, versioned platform APIs and SDKs with client interfaces and examples.
• Build FastAPI services for enforcement decisions, evidence, policies, and results.
• Design authentication, sessions, API keys, authorisation and multi-tenant isolation.
• Create data and event interfaces, real-time streams and tamper-evident audit ledger.
• Develop customer onboarding, policy integration and operator dashboards.
• Own testing and deployment across API compatibility, browser tests, Cloud Run and Cloud SQL.

Skills

Backend APIs

Python

FastAPI

Observability

Relational databases

API design

Authentication & multi-tenant

JavaScript & React

Independent work

Tools

PostgreSQL

Git

Cloud Run

Cloud SQL

Job description

Refractal, a London-based AI security company, seeks a product-minded platform engineer to own the core platform APIs, SDKs, and multi-tenant services. You will work with the founders to translate operational security needs into reliable interfaces and operator tools.

You will design authentication, API keys, session handling, and real-time data interfaces while ensuring robust testing, deployment, and customer integration across Cloud Run and related services.