Backend Engineer - AI PropTech Startup

London, Hybrid (weekly office attendance preferred, min. 1-2 days)

Level: Senior

We're working with a 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 workflows

The 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 Role

The 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 organisation. The right person will own services end-to-end, in a fast-growth environment where priorities shift and velocity matters.

What They're Looking For

• Fast-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 For

• No FastAPI / weak Python
• Unable to travel to the office 1-2 days a week
• Purely frontend focus with no backend service ownership
• No evidence of scale-up or agentic development experience
• Ultra-high performers from AI-first rocketships (salary expectations typically exceed range)

Ideal Background

Strong 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.