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