Middle Fullstack Engineer

Title: Fullstack Engineer

Location: Paris, IDF, FR / Paris, Île-de-France, FR / Remote (FR)

Own the platforms that collect, check and pay for the data behind the largest AI and robotics models.

### About Hub

Hub is one of the fastest-growing data companies, providing real-world training data to the largest AI and robotics companies. Based in San Francisco and backed by Y Combinator and top VCs, our mission is to advance embodied AGI through real-world data and research.

### The role

As a founding engineer you own some of the most critical systems in the company, and you understand why they matter to the business as much as how they work. We keep the word founding on purpose: this is where our future tech lead comes from.

### What you'll own

\- Multiple platforms with 150K+ users collecting data: contributor app, commercial platform, mobile app and internal tools.

\- The mobile app, which is becoming our main way to collect data for the World API.

\- Anti-fraud and automated QA systems. You own the quality of what we deliver every day.

\- Heavy backend work, keeping architecture and ops efficient as we scale to 1M+ users.

\- Payout systems moving high daily volumes of money across 100+ countries.

\- Live production for several of the top 5 AI companies, with hard deadlines and specs.

\- Turning what the founders need this week into features, and deciding what not to build.

### You might be a fit if

\- 1 to 5 years of experience as a full-stack engineer. More is welcome when the track record justifies it.

\- Your education includes classes préparatoires then a grande école.

\- Business sense: you've been a founder, a founding engineer at a startup (ideally YC), or added business training to an engineering degree.

\- Exceptional individual achievement: elite rankings at competitions or concours, hackathons won, a system you hacked, projects with real users or revenue.

\- Active programming you can show: real GitHub contributions, open-source work, projects you built on your own.

\- Agentic engineering as a craft. You run several agents in parallel, with a harness you've tuned, and give them a way to check their own work.

\- Fluent English, spoken and written.

\- Ready to commit fully to our scale-up phase, with strong ownership and focus.

###

Nice to have

\- French, spoken and written. A big plus.

\- You've shipped mobile apps on iOS or Android, ideally with React Native.

### Stack

\- Python, FastAPI, Postgres, React, Docker, AWS and S3, versioned REST APIs.

\- Mobile: React Native and Expo, one codebase for iOS and Android, ARKit and ARCore for egocentric video capture. RGB and IMU sync, MCAP output.

\- Multimodal pipelines at petabyte scale: ingestion, VLM QA and labeling, fraud detection, stereo depth and hand reconstruction, delivery in MCAP and LeRobot.

\- Everything built in-house, not assembled SaaS.

###

What we offer

\- $80,000 to $120,000 yearly salary.

\- Stock options between 0.05% and 0.2%.

\- Remote, or from our Paris or São Paulo office.

\- Direct work with the founders and with top AI labs.

### How we hire

1\. A short application read by the team. We open your GitHub and handles first.

2\. A first conversation about you, Hub and the role.

3\. You run npx standout in your terminal with no docker. No take-home, we look at how you already work.

4\. A conversation with our co-founder.

5\. An answer within 48 hours.

### How to apply

Send a short application in your own words:

• \- Your CV

\- The thing you've built that you're most proud of

\- Your GitHub and other handles

\- The story behind it