Founding AI Engineer, right hand to the CTO

Supply Finder at a glance

• A programmatic supply decision platform: for every campaign, it finds the inventory that will perform across 10+ SSPs and keeps tuning it, so buying teams deliver what they sold.
• Founded in 2025 by three founders from adtech, with 21 years of combined experience on the SSP side.
• Already in production: 10+ buying teams, 10+ SSPs connected, 3 continents.
• Measured results: on a published A/B test, -45% cost per video view and -49% CO2 per 1,000 impressions.
• Funded: a pre-seed round closed with business angels, completed by Bpifrance and bank financing.

The role

You are the right hand of Antoine, our CTO, and the first pillar of the tech team. You own the agent and decision layer; Antoine keeps the overall architecture and the technical roadmap, and you set priorities together.

• Reporting line: to the CTO, with a scope and decision rights written down from day one.
• What you own: the agent and decision layer, and the technical integrations with our partners.
• Your impact: every improvement to the decision shows directly in the performance of our clients' campaigns, and lets every trader run more.
• What comes next: when the tech team grows, you will be its first point of reference.

What you will build

1. The product's AI agents. Our agents already support buying teams, from the brief to campaign monitoring. You make them grow: new capabilities, reliability, evaluation, shipping to production.
2. The decision models. What finds the inventory that will perform for each campaign and improves it in flight. Your data and ML background matters here.
3. New partner integrations. SSPs, platforms, data sources: you connect new partners and make those integrations solid.
4. New product lines. New channels and new use cases are on the table. You take part in designing them, from technical scoping to production.
5. The product opened to AI assistants. Supply Finder already exposes its capabilities to AI assistants through an MCP connector. You grow that opening.
6. The foundations. Tests, CI, monitoring, code review, product instrumentation: what lets us move fast without breaking things.

The stack

You do not need to know adtech when you join: we teach it, it has been our job for more than 20 years.

How we work

A startup does not have to mean vagueness. Here is the framework you will find when you join.

• A written scope. What you own, what you decide alone, what gets settled with the CTO: it is in writing from day one.
• A quarterly roadmap. Priorities are set by the founders and shared; we do not change course every week.
• Simple rituals. A weekly product and tech meeting, systematic code review, a monthly demo of what shipped.
• A 30, 60 and 90-day onboarding. The business, the codebase, then your first deliverables on your own, with clear goals at each stage.
• Solid ground. A permanent contract, a funded company, clients who pay every month.

Your profile

Above all

We are looking for someone resourceful, curious and frankly geeky. The kind of person who loves tech well beyond their job: you follow what comes out, you take things apart to understand how they work, you try a new tool the day it ships. When nobody has told you where to start, you find a way anyway.

Must have

• 3 or more years in software engineering, including LLM-based systems in production: agents, RAG, tool calling.
• Solid Python, in production.
• You have already shipped, monitored and evolved systems used by real clients.
• You can take a vague topic, scope it, break it down and ship it.

Nice to have

• A background in data science or ML: forecasting, scoring, optimisation.
• Experience with MCP or with LLM evaluation.
• TypeScript and front end.
• MongoDB, data pipelines and third-party API integrations.

Adtech experience is not required.

Package and terms

The process

Four steps, a reply within 48 hours after each.

1. First conversation with Maxime, CEO: the project, the role, what you expect.
2. Technical interview with Antoine, CTO: we start from a system you built and dig into your choices.
3. Working session: a real agent design problem, worked on together.
4. Meeting with the three founders, then an offer.

To apply: the form below, with your profile and a project you are proud of.