Contract - Back End Developer - Python/AWS - £500-£700/day (Outside IR35) - ID44270

Senior Backend Engineer – Python | Django | FastAPI | AWSCheck you match the skill requirements for this role, as well as associated experience, then apply with your CV below.

Build systems that power the future of AI

Are you a high-agency backend engineer who thrives on solving complex problems at scale?

Do you enjoy designing secure, production-grade systems and shipping robust APIs that make advanced technology accessible?

Would you like to shape core infrastructure for AI-powered products in a fast-paced, ambitious environment?

If this sounds like your kind of challenge – this could be the opportunity that unlocks your next big career move.

About the Role

Our client – an innovative, deep tech start-up based in the UK – is seeking a Senior Backend Engineer with expertise in Python (Django or Flask) to architect and deliver production-grade systems for cutting-edge AI products. This is a role for engineers who enjoy owning backend services end-to-end – from design to deployment and everything in between.

You'll play a pivotal role in building secure, scalable APIs, optimising infrastructure, and integrating backend services directly with AI models and real-time inference pipelines.

This is a hybrid role with flexible hours, offering rapid career progression and a chance to define best practices from the ground up in a company that genuinely values engineering excellence.

Why This Role is Great

In this role, you'll get to:

• Design scalable backend architecture using FastAPI and Python for high-performance workloads
• Build and maintain robust APIs following RESTful conventions and OpenAPI/Swagger standards
• Own the performance of PostgreSQL databases, including partitioning, indexing, and horizontal scaling strategies
• Secure and optimise infrastructure using Docker, AWS, and infrastructure-as-code (IaC) tools like Terraform
• Collaborate directly with AI and product teams, translating real-world requirements into elegant backend systems
• Mentor engineers and influence architecture, driving backend standards and operational excellence
• Take full ownership of systems in production, including logging, monitoring, incident response, and disaster recovery

About You

You might come from a variety of backgrounds, but you'll thrive in this role if you're excited to:

• Work with modern tools like Python, FastAPI, PostgreSQL, Docker, and AWS
• Engage with real-time systems and AI model integration pipelines
• Build on your experience of deploying APIs, writing clear documentation, and maintaining strong testing practices
• Apply your knowledge of CI/CD tools like GitHub Actions or Argo CD to ship high-quality code fast
• Be hands-on with authentication systems (OAuth2, OIDC) and secure API design
• Operate with a security-first mindset, using tools like GuardDuty, CloudWatch, and IAM best practices
• Grow in a high-trust, high-ownership culture where autonomy is valued and impact is recognised

Ideal Skills Wishlist

(If you meet most of these, we'd love to hear from you!)

• 5+ years of backend engineering, ideally in Python with Django, Flask, or FastAPI
• Proven experience building REST APIs in production
• Strong command of relational databases (especially PostgreSQL)
• Familiarity with containerisation (Docker) and version-controlled environments
• Hands-on AWS experience (VPC, EC2, S3, IAM, ALB/ELB, etc.)
• Exposure to CI/CD practices and infrastructure-as-code
• Comfortable leading backend projects and mentoring peers
• *Active MoD SC*

Diversity & Inclusion

We're committed to building teams that reflect a broad range of backgrounds, perspectives, and skills – and so is our client. We actively encourage applications from all genders, ethnicities, abilities, and experiences. If you're passionate about backend engineering and think this role sounds exciting – even if your CV doesn't tick every box – we encourage you to apply.

Ready to Make a Real Impact?

If you're ready to join a team building AI systems that work at scale in the real world, we'd love to hear from you.

Apply now to start a conversation about your next chapter as a Senior Backend Engineer.