Full-Stack Engineer - Full-time position

About HyLight

Power lines, gas pipelines and railways are still inspected the way they were 50 years ago: by helicopter. Expensive, noisy, and up to a tonne of CO₂ per flight hour.

We built the alternative. The HyLighter is a 12-metre autonomous airship running on hydrogen. It flies for up to 10 hours, almost silently, and spots a 1 mm defect from 25 metres up.

But the airship is only half the story. Every flight brings back massive amounts of LiDAR, imagery and methane data, and that’s where the value is. Our AI turns it into what operators act on: 50+ types of defects detected automatically, and leaks pinpointed across their network.

It’s not a prototype. HyLighters already fly missions for France’s largest energy and rail operators and have flown over the Palace of Versailles. Backed by Y Combinator, we just raised €13M to go from 4 airships to 15.

Working at HyLight

We design, build and fly every HyLighter, and turn its data into insight, all under one roof on a former airbase. Which means:

• You own it all the way. At a big aerospace company, you’d own a small piece of one subsystem. Here, you design it, test it, stand on the airfield when it flies, and see the client act on the data it brings back.

• Weeks, not years. Ideas go from whiteboard to flight test in weeks.

• Responsibility from day one. The founders’ average age is 27. Nobody here waits for permission.

We don’t care about titles or ticking every box. We care about what you build and the perspective you bring, so if your profile is different, apply anyway.

Job Summary

The Platform Team makes the bridges between each team - building the tools to deliver reliable, unified solutions meant to industrialize our processes and keep everyone focused on what matters most. As we scale toward industrial volume, the bottleneck is no longer just flying - it's everything around the flight. We're looking for an experienced Full-Stack Engineer to join the Platform Team, help us build the internal tools, ground station software, and cross-team automations that keep HyLight moving, and support the existing team in what they're already shipping.

Responsibilities

• Ship internal applications the team relies on every day - mission planning, fleet & inventory tracking, post-flight review, regulatory dashboards, CRM-adjacent tooling.

• Own the business model in code. Embed yourself with the teams you build for, learn how the company actually operates, and translate that into clean data models and the right abstractions.

• Kill manual workflows. Identify the repetitive, error-prone steps slowing the company down - compliance paperwork, team hand-offs, status updates - and replace them with software.

• Integrate the tools the team already uses (Notion, Slack, GitHub, OnShape) so data flows automatically and a single source of truth exists across the company.

• Tackle hard, domain-specific problems: help operations turn a vast set of criteria - weather, airspace, regulation, fleet availability, mission objectives - into a concrete flight schedule.

• Contribute to the ground station - telemetry dashboards, sensor feeds, and pilot-facing tools - working closely with the embedded team on clean contracts between the aircraft and the ground.

• Design and maintain the APIs and services supporting frontend applications and integrations.

• Build automations and AI-powered tools that give the team real leverage.

• Own what's already running: fix bugs, refactor when it earns it, monitor reliability, and make sure what the team depends on every day keeps working.

Skills and experience sought

Education & Experience

• Bachelor/Master in Computer Science, Software Engineering, or equivalent practical experience.

• A few years of experience building and shipping full-stack web applications - we care about what you've built, not where you studied.

• Track record of end-to-end ownership: you've shipped things, dealt with production messiness, and kept going.

• Genuine interest in building tools that people inside a company use and depend on every day.

Technical Skills

• Strong systems thinking: you reason about how components fit together at scale, design for reliability, and make architectural decisions you can live with as the product grows.

• Frontend: React / Next.js, TypeScript, TailwindCSS.

• Backend: Node.js (NestJS, Express) or Python (FastAPI), REST APIs, PostgreSQL.

• Full delivery stack as baseline: Git, Docker, AWS or Railway, CI/CD - these are not bonus points.

• Testing: you write tests as part of shipping, not as an afterthought - unit, integration, and end-to-end coverage where it matters.

• Bonus: GIS / geospatial stacks (MapLibre, Mapbox GL, PostGIS, GeoJSON), C/C++.

Soft Skills

• Curious. You ask why things are built the way they are, and you go figure it out when no one answers.

• Open-minded. You hold opinions strongly, but you change them when shown something better.

• Genuinely autonomous. Hand you a fuzzy problem, you come back with a v1 and the right follow-up questions - not waiting to be told the next step.

• Passionate. You genuinely care about what you do - you build, you read, you tinker, you have opinions.

• At home in a high-pace environment. Priorities shift, decisions are made fast, reality wins over plans. You see that as fuel, not friction.

AI Leverage

We're building HyLight as an AI-native company - not as a buzzword, but as a genuine way of working. We believe the engineers who'll shape the next decade are the ones who've learned to multiply their output with AI, not just occasionally use it.

• You use AI tools fluently as part of your daily workflow - Cursor, Claude Code, Copilot, or whatever gives you the edge.

• You think about where AI can replace a workflow entirely, not just assist with it.

• You're curious about what's emerging and you experiment - you don't wait for the tooling to be mature.

If you've built something AI-powered, shipped an internal agent, or just have strong opinions on how to use these tools well - we want to hear about it.

Additional requirements

This role is based at Base 217, Brétigny-sur-Orge (accessible via RER C). Remote work is part of how we operate, though regular presence on the base matters - it's how you stay close to the teams you build for and understand what they actually need. Flight operations run on their own cadence, which can naturally extend into irregular hours or weekends.

English is required for internal communication and documentation. French is a plus.

What We Offer

• Potential to become a shareholder in HyLight.

• Real ownership and direct impact from day one - you're not a resource, you're a builder.

• Excellent work environment: international team, beautiful offices on a former airbase - flights happening right outside the window.

• Bi-annual offsite trips with the whole team.

• 100% reimbursement of public transport pass (Navigo) or €800/year for sustainable commuting.

• Bike provided for commuting.

• Free lunch.

• Access to a sauna and gym on-site.

• Hybrid : remote days can be done.

Why You Should Join

• Founder Mentality : We value extreme ownership and want people who think like founders-fast decision makers, natural problem solvers, and executers.

• Ground Floor Opportunity : You’ll be helping to shape and grow a revolutionary company with the resources to back it.

• I mpact & Speed : Work in a fast-paced environment where your contributions will have immediate, tangible effects on the company’s success.

Interview Process

• Introductory phone call (20-30 min)

• Take home assessment

• Technical discussion

• On-site meeting with the team (3-4h)

• Reference Calls

Location

• Office : Base 217, Brétigny-sur-Orge, accessible via RER C.

• Lab and Warehouse access