As the third founding engineer at this London Bridge-based startup, you will build agentic AI systems that automate complex accounts receivable workflows. You'll transform unstructured contracts into live invoicing and revenue recognition engines, working directly with the founders to replace manual spreadsheets with deterministic, AI-driven financial infrastructure in a fast-paced, in-office environment.
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London, UK£100-130k + 0.6-0.8% Equity
Featured roleLondon, UK£100-130k + 0.6-0.8% Equity
Founding Engineer at Spinal — VC-backed AI startup
Join Spinal as a Founding Engineer and build the AI-powered future of finance. Based in London Bridge, we're a venture-backed startup replacing manual spreadsheets with agentic AI that reads contracts and automates billing end-to-end. As one of our first five employees, you'll own the architecture, ship daily to production, and hold a significant equity stake. If you're a Python expert who thrives in a high-intensity, in-office environment and wants to solve complex problems with LangGraph and Temporal, this is your chance to shape a company from its earliest days.
Overview
Why this role stands out
Company
Spinal - VC-backed AI automation for modern finance teams
Responsibilities
What you will do
- Design and deploy agentic AI systems that extract complex billing terms from unstructured legal documents and PDFs.
- Architect and maintain robust backend services using Python, Pydantic, and Postgres to power end-to-end collections and revenue recognition.
- Collaborate directly with the CTO to translate customer needs into production-ready features that eliminate manual finance workflows.
Candidate profile
Who this is a fit for
- 3-5 years of experience as a Python backend engineer with a proven track record of shipping complex systems from zero to one.
- Hands-on expertise with agentic AI frameworks such as LangGraph or LangChain, specifically for processing unstructured data into structured outputs.
- A founding mindset demonstrated through previous early-stage startup experience, academic distinction, or a high-performance background in competitive fields.
What makes it remarkable
Why this role is remarkable
- Join as employee #5 with a true founding equity stake and direct influence over the architectural evolution of the core product.
- Build at the cutting edge of agentic AI using LangGraph and Temporal to solve high-stakes, multi-billion dollar problems in finance.
- Work in a high-intensity, collaborative environment in London Bridge with a team that prioritizes shipping fast and weekly demo sessions.
Jack & Jill
How Jack & Jill work together
I get to know what you’re great at, then find roles you’d never find yourself.Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
I recruit from Jack’s network and make the intro when I spot a great match.And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
About Jack & Jill
Meet Jack
Jack gets to know what you are great at, what you want next, and makes sure Jill considers you for the right opportunities.
How does this work?
Jack's an AI agent for job searching and career coaching. He works for you.
Jill is the AI recruiter working for the company. She recruits from Jack's network.
If it's a match and the company wants to meet you, they'll make the intro. In the meantime, if you'd like, Jack will send you excellent alternatives.
Jack