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Twelve

Senior Full Stack Engineer - AI Systems

Remote

United kingdom

Senior

Full Time

23-02-2026

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Skills

Python TypeScript Decision-making Autonomy react Next.js FastAPI PostGres

Job Specifications

Senior Full Stack Engineer (AI Agentic Systems)

Replacing static dashboards with a platform where AI agents help leaders make high-stakes procurement and sustainability decisions in real-time - building the intelligence layer for global supply chain decisions.

Join a lean, flat, high-velocity team of builders. Every engineer owns outcomes end-to-end—from the data pipeline to the agentic orchestration to the frontend.

Moving beyond "chatbots" to create collaborative intelligence. Our agents don't just generate text; they orchestrate a complex digital twin of physical reality, modelling price cascades, carbon footprint calculations, and global supplier networks.

We are looking for engineers who are highly collaborative but thrive in ambiguity, ownership and autonomy. You will define your own roadmap, write your own briefs, and ship code across the entire stack.

Key Skills:

You build production AI, not just demos. You have experience with agentic orchestration (e.g., LangGraph), tool-use patterns (MCP/function calling), and robust RAG systems.
You are a Python expert. You can build the domain services, calculation engines, and data pipelines (FastAPI, Dagster) that serve as the agent's "tools".
You are comfortable across the stack. While you might lean toward the backend or AI layer, you can navigate Next.js, TypeScript, and React to wire outputs into the UI.
You have "Domain Curiosity." You find the complexity of physical supply chains, refineries, feedstock pathways, and regulatory filings genuinely interesting.

Our Tech Stack

AI/Agent: LangGraph, MCP, Voyage AI embeddings.
Backend: Python (FastAPI), Neon Postgres, Dagster.
Frontend: Next.js, TypeScript, MUI/MUI X, and AI-generated UI patterns.

What We Offer

True Autonomy: No approvals, no red tape. You have decision-making power at the edge.
Competitive Compensation: £70K–£130K (based on experience) + meaningful early-stage equity.
Flexibility: London-based or Remote within European time zones.

If you tick some but not all of the boxes mentioned but think this role sounds exciting then please do still click apply - we'll be in touch if it's worth a chat or if any other more suitable roles come up.

About the Company

Tech hiring has been the same for decades. Overpriced. Slow. Inefficient...what if it wasn't? Our founders have combined 30 years expertise across exec search, internal rec and agency. They've led talent strategy for companies like Trainline, Moonpay and Checkout, and recruited for 100's of tech brands like McKinsey, Just Eat, and Monzo. Salaries in the technology sector have risen faster than inflation for years, meaning recruitment fees have enjoyed the same trend. In a market where tech talent is more accessible than ever... Know more