Lead Full Stack Developer

Join our team as a Lead Full Stack Developer, where you'll have the opportunity to lead and set direction while staying hands-on with coding. You'll be responsible for building and maintaining a robust backend and cloud infrastructure, as well as translating commercial and product priorities into technical work. This hybrid position is based in Central Paris, with 1-2 days per week on-site.

Responsibilities

• Implement, maintain, and continuously improve a robust, scalable, high-performance backend and cloud infrastructure.
• Translate commercial and product priorities from the leadership team and internal stakeholders into technical work, and give an honest read on cost, risk, and sequencing before anything is committed.
• Define what the team needs, run technical interviews, make the call on candidates, and own whether people ramp up well.
• You report to the CTO (Aaron) and work alongside two senior software engineers (Sylvain and Tim). You are the technical authority on the platform and the day-to-day lead for the team.

Requirements

• Professional fluency in English (C1/C2).
• Advanced programming skills in Python 3.12+, and JavaScript (or TypeScript).
• Product judgment. You can tell the difference between a request and a requirement, and you have opinions about what should be built that you are willing to defend and to drop.
• Senior-level experience building and operating back-end systems in critical production environments, including a period as tech lead, lead developer, or the de facto technical owner of a small team.
• Working front-end experience. You do not need to be a front-end specialist, but you need to be able to ship a feature end-to-end without waiting for someone else, and to review front-end work credibly.
• Ability to explain and trivialize technical subjects clearly to non-technical audiences
• Real experience with GCP or an equivalent (AWS, Azure), or a clear willingness to get there fast.
• Analytical and critical thinking, the ability to take responsibility for quality from prototype to production, and the ability to say no.
• Fluency with AI-assisted coding tools (Claude Code and similar), including the ability to critically evaluate AI-generated code and continuously improve internal procedures.
• Comfort with a die and retry philosophy: fail fast in development, rigor in production.
• A genuine interest in producing battle-tested, production-grade code within a distributed environment, and in staying current on software engineering and security.
• Entrepreneurial mindset: you find solutions, take initiative, and accept that at our size responsibilities do not come in neat boxes.

Preferred

• High bonus: familiarity with IoT, MQTT, or building automation (HVAC).
• High bonus: networking knowledge: routers, VLANs. You will be asked to handle those.
• Ability to challenge existing architectures, including ones that have worked for years.
• True fullstack experience (from prototype to production, any framework, any language) and the ability to maintain a production fleet.
• Infrastructure as code with Terraform.
• You are curious and willing to learn. So are we. Even if you do not tick every box, we encourage you to apply.

• We have no dedicated ops team (yet), so running your own services in production is part of the job. There is no on-call rotation.
• This is a hybrid position based in Central Paris, 1-2 days per week on site. The alignment part of this role works better in person, and the people you will be translating for are here.