Senior Python Backend Engineer

Your Mission The purpose of this role as Senior Backend Engineer is to design and build the scalable, secure Python backend and services at the heart of our AI governance platform. This is a hands-on, high-impact individual-contributor role at the centre of a fast-moving start-up: you’ll own backend architecture and delivery, make pragmatic technical decisions, and translate complex, governance-led product thinking into robust, well-tested services that the business customers who rely on us can trust. You will report to the Director of Technology and work in close, day-to-day collaboration with the wider engineering team and Lead Developer — underpinning the rapid launch and development of our AI-native service. You’ll be joining early enough to shape not just the platform, but how engineering happens. The Role The Senior Backend Engineer role sits at the intersection of backend engineering, cloud infrastructure and AI-augmented delivery. You will take backend architecture from concept through to production, focusing on a scalable Python backend on AWS, well-designed APIs and distributed systems, and harness-based AI-assisted development workflows. Key Responsibilities ● Architect and build a scalable, secure Python backend on AWS, including distributed systems, asynchronous architectures and well-designed APIs. ● Own backend services end-to-end — data modelling, performance, reliability, observability and security. ● Work hands-on with cloud infrastructure using Terraform, Kubernetes and EKS to deploy and operate your services. ● Use harness-based, AI-assisted development workflows — running Claude Code or similar coding agents in automated loops to handle the majority (80%+) of the SDLC, from planning through implementation, testing, and review. ● Set and uphold backend engineering standards: code quality, CI/CD, testing, and release practices. ● Partner with front-end engineers and the UI/UX Lead to design clean, well-documented API contracts. ● Contribute to technical direction and roadmap discussions with the Director of Technology and founders. ● Use AI tools throughout your own workflow — for planning, coding, testing and review — to accelerate delivery without compromising quality. ● Continuously look for better ways of working — in your process, your tools and your output. Profile ● 5+ years’ experience in shipping production backend software as a senior engineer. ● Strong Python backend development experience (5+ years) in scalable, production systems, including distributed systems, asynchronous architectures and APIs. ● Solid hands-on AWS experience (5+ years), with strong DevOps exposure to Terraform, Kubernetes and EKS. ● Deep understanding of API design, data modelling, performance, reliability and observability. ● Hands-on experience developing software using Claude Code or similar AI coding agents, running them in automated loops and using them to drive 80%+ of the SDLC (planning, coding, testing, review). ● Comfortable owning backend architecture decisions. ● Professional experience with familiarity with LLM-based systems or AI/ML product development. ● Comfort operating in an early-stage, fast-changing environment, where priorities shift and ambiguity is normal — someone who leans into that rather than waiting for certainty. ● Excellent collaboration skills, working as an equal partner to product and other engineers. ● Master’s degree in a STEM field (Computer Science, Software Engineering, or related discipline). ● Nice to have: experience in governance, compliance, security, or regulated industries. ● Nice to have: prior experience at an early-stage startup, ideally pre-Series A. The Problem You’ll Help Solve In this role you will help address challenges such as: ● ensuring complex technologies remain transparent and accountable ● helping organisations adopt AI safely and responsibly ● building governance systems that support innovation rather than slow it down. What You’ll Help Build The initial build of all new product capabilities including: ● designing and building the scalable backend and infrastructure underpinning corporate memory and governance frameworks for advanced technologies ● building and continuously improving technology platforms ● working with partners to co-create new tools and capabilities ● translating complex technical or regulatory concepts into practical, shippable engineering solutions ● contributing to the evolution of products, research, or partnerships. What Success Looks Like Success in this role will be defined not just by tasks completed, but by the impact created. Examples may include: ● A reliable, scalable and secure backend that supports rapid product iteration ● Well-designed APIs and services that other engineers can build on with confidence ● Highest levels of security and compliance including SOC2, Cyber Essentials Plus and ISO, enabling a capability that sails through due diligence ● Clear linkage between backend delivery and commercial growth We look for people who take ownership of outcomes and continuously seek better ways of working. Practical Details Location: London, UK (Hybrid — 3 days/week in office) Team: within the Engineering organisation Role Type: Permanent, full-time role Salary: £85,000 to £110,000 p.a. salary Right to work: Applicants must already hold the right to work in the UK. We are unable to sponsor visas for this role Reports to: Director of Technology Works closely with: the wider Engineering team, and Lead Developer Please provide your current residential location when applying. Please note. At Alexander Charles we take the protection of your data very seriously and I would draw your attention to our GDPR statement which can be found on our website under the heading “legal” By sending us your details, you will have deemed to have considered and accepted these terms.