Senior Python Engineer (FastAPI) – Sustainable Tech Company (Well backed) – £90k

A UK-based infrastructure and technology leader are looking for a Senior Backend Engineer to help build and scale a mission‑critical platform that connects software with real‑world infrastructure.

You’ll join at a key point in the journey: replacing a legacy SaaS platform with a modern, in‑house solution, then extending it into a genuinely market‑leading product – All Greenfield!

What you’ll be doing

• Designing and building backend services using Python and FastAPI
• Owning and evolving core APIs and platform components
• Working on distributed, event‑driven systems that interact with hardware in the real world
• Improving performance, resilience, and observability across production systems
• Collaborating closely with product and design to deliver meaningful features
• Mentoring other engineers and setting a high bar for code quality and architecture

What they’re looking for

• Strong experience building production backend systems at scale
• Deep knowledge of Python and modern API design
• Experience working in AWS
• A pragmatic, opinionated engineering mindset
• Ownership mentality and comfort working in a fast‑moving environment

Experience with IoT, hardware integrations, protocol‑driven systems, or payments is highly desirable, but strong fundamentals and good judgement matter most.

3 days a week in London

Paying up to £90k + 15% bonus

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