Founding Engineer (100-130k + 0.8 Equity) at Spinal

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Job Title: Founding Engineer

Salary: 100-130k 0.6-0.8% Equity

Company Description: Spinal - VC-backed AI automation for modern finance teams

Job Description:
As the third founding engineer at this London Bridge-based startup you will build agentic AI systems that automate complex accounts receivable workflows. Youll 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.

Location: London UK

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.

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.

The ideal candidate:

• 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.

Who are Jack & Jill
Ok Ill go first. Im Jack an AI that gets to know you on a quick call learning what youre 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.
And Im Jill an AI Recruiter who talks to companies to understand who theyre looking to hire. Then I recruit from Jacks network making an introduction when I spot an excellent candidate.

Next steps
Step 1. Visit our website.
Step 2. Click Talk to Jack.
Step 3. Talk to Jack so he can understand your experience and ambitions.
Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.
Step 5. If Jill thinks youre a great fit and her client wants to meet you they will make the introduction.
Step 6. If not Jack will find you excellent alternatives. All for free.

We never post fake jobs
This isnt a trick. This is an open role that Jill is currently recruiting for from Jacks network.
Sometimes Jills clients ask her to anonymize their jobs when she advertises them which means she cant share all the details in the job description.
We appreciate this can make them look a bit suspect but there isnt much we can do about it.
Give Jack a spin! You could land this role. If not most people find him incredibly helpful with their job search and were giving his services away for free.

Required Experience:

IC