Senior Backend Developer - Python

Senior Backend Engineer - Python

Outside IR35

Hybrid - Oxford or London | Contract

Our client, a UK-based deep tech start-up, is seeking an experienced Senior Backend Engineer (Python & Django or Flask) to own and operate mission-critical backend services powering generative AI products. You'll architect, build, and run scalable APIs and data services end-to-end, collaborating closely with AI engineers to deliver new features from concept to production. This role offers the opportunity to shape the backend systems at the core of cutting-edge AI, with a strong focus on performance, reliability, and security.

Key Responsibilities

• Architect and evolve scalable backend services in Python (FastAPI / Django / Flask).
• Design and operate RESTful APIs aligned with OpenAPI / Swagger.
• Implement authentication and authorization (OAuth2 / OIDC, permissions, session management).
• Optimise relational database design and performance (PostgreSQL).
• Introduce caching, rate limiting, and queuing to meet performance goals.
• Integrate with AI pipelines and model-serving endpoints (async inference, streaming).
• Containerise services with Docker; maintain IaC with Terraform / CloudFormation.
• Operate services on AWS with CI / CD pipelines (GitHub Actions / Argo CD).

Lead security hardening, monitoring, and compliance read...