Backend Engineer - AI PropTech Startup

Backend Engineer - AI PropTech StartupLondon, Hybrid (weekly office attendance preferred, min. 1-2 days)Salary: To £100,000Level: SeniorWe're working with an PropTech start-up to find two Senior Backend Engineers to join their team as they build out a genuinely green-field AI product from scratch.They're launching two parallel AI workstreams:Augmentation - AI assisting operations teams on complex, high-risk tasks (finance, invoicing)Automation - fully automating high-volume, low-risk repetitive workflowsThe core mechanic is benchmarking LLMs to perform automated steps in workflows. For engineers frustrated by bolt-on AI at their current employer, this is the opportunity to build it properly from day one.The RoleThe successful candidate will own and develop the core applications powering the business - primarily CRM and finance services - for both internal and external users. They'll work in one of two small engineering teams (3-4 engineers), hands-on from day one, shipping fast using agentic development workflows.This isn't a role for someone used to delegating in a large org. The right person will own services end-to-end, in a fast-growth environment where priorities shift and velocity matters.You'll work in one of two small engineering teams (3–4 engineers), hands-on from day one, shipping fast using agentic development workflows.This is not a role for someone used to delegating in a large org. You'll own services end-to-end, in a fast-growth environment where priorities shift and velocity matters.What They're Looking ForFast-growth startup / scale-up experience. Candidates should have worked at a Stealth Start-up/Series A/B startup through a period of rapid scaling, and be comfortable with ambiguity, shifting priorities, and shipping under pressure without over-engineering. Early or founding engineer experience, ownership of significant surface area, and demonstrable velocity are all a strong fit.Strong, current production Python with FastAPI - this is a hard requirement. Experience with API design, async Python, and SQL/ORM is a plus.Genuine, current use of agentic development workflows. Candidates should actively use AI coding agents (e.g. Claude Code, Cursor) as a core part of how they work, and think about optimising their own and their team's development workflow - tooling, automation, spec-driven development.Ownership of quality. Writes and maintains their own tests, and is comfortable in a "you build it, you run it" culture.What They're NOT Looking ForNo FastAPI / weak PythonUnable to travel to the office 1-2 days a weekPurely frontend focus with no backend service ownershipNo evidence of scale-up or agentic development experienceUltra-high performers from AI-first rocketships (salary expectations typically exceed range)Ideal BackgroundStrong candidates typically come from lean, fast-scaling product companies with a genuine engineering culture (rather than large corporates, agencies/consultancies, or businesses without a strong tech function), bringing hands-on, current experience shipping production Python/FastAPI services alongside real agentic-AI-assisted development practice.If you're frustrated by bolt-on AI at your current employer, this is the opportunity to build it properly from day one.