Fullstack Engineer
Confirmed on the employer's own hiring board on Oct 4, 2026. First seen by Alion on Sep 12, 2026.
About Sitemark
Sitemark is the AI and robotics platform for building and operating renewable energy. The world's leading Owners, EPCs, and O&M companies use Sitemark.
What problem are we solving and why is this important to solve:
The world is building one of the largest infrastructure shifts in history - and it needs better tools to get it done. Renewable energy projects are growing in scale, complexity, and urgency, but the teams responsible for building and operating them are stretched thin - buried in repetitive work, disconnected systems, and running out of time. That's why we built Sitemark: AI and robotics take the repetitive load off these teams, from the field to the office, so their time goes to what matters - and sites get built faster and perform better.
The team you'll join:
You will join an extremely talented team of incredibly passionate, high-energy people. We go the extra mile while having the best time of our lives.
How we operate:
We care deeply about our customers and the problems we solve for them.
We move fast, keep things simple, and focus on what matters.
We keep our quality bar high by staying lean and hiring only the best.
Tasks
As a Senior Full-Stack Engineer, you'll own the development of impactful features end to end - from speccing and prioritization through to production and validation. You own real problems and the outcomes they drive: the quality, performance, and evolution of the platform our customers rely on every day. You think like a product person - caring about the user and the outcome, not just the ticket - and you have a real say in what we build, not just how.
Most of all, you'll be building with and for our customers. You'll talk to them directly, understand their problems, and turn what you hear into solutions that genuinely work for them. That close contact is where the best ideas come from, and it's a big part of the day-to-day.
In how you build, we have a strong point of view: the future of engineering isn't writing more code by hand - it's building the systems that write it. AI handles much of the writing, which frees you to work at a higher level - on the product, the architecture, and the problems worth solving. It's a higher-leverage, and more exciting way to build.
What this role is not
It's not heads-down ticket-taking - you shape the product, not just implement it.
It's not vibe-coding - AI is leverage for engineers who deeply understand their systems, not a shortcut around real engineering.
It's not building in a silo - you stay close to the customers you're building for.
What you'll do:
Lead features and projects end to end - from spec and prioritization through development, testing, and deployment.
Shape what we build, not just how - bring ideas to product refinement, brainstorming, and prioritization as a genuine product thinker.
Work directly with customers - understand their problems firsthand and turn them into technical solutions.
Own architecture and the hardest problems. You make the calls on how systems fit together and what "good" looks like, take on the toughest technical challenges, and you can read, debug, and harden anything that gets built.
Build with AI as your default: direct it, review it, and ship far more than you could by hand - without ever shipping something you don't understand or can't stand behind.
Share what you know, and help the team get better every day
What success looks like after 6-12 months:
You've shipped impactful features end to end, and you're trusted to own them from problem to production.
The platform is measurably better - faster, more reliable, more capable - because of your work.
You're shaping what we build, not just how, and it shows in the product.
Customers are getting solutions that genuinely fit their problems, because you were close enough to understand them.
Requirements
Strong fluency in modern JavaScript/TypeScript, with React and Node.js.
Solid understanding of, or a strong interest in, full stack development and cloud infrastructure (PostgreSQL, Azure, AWS, Docker…).
You write clean, maintainable, reusable code with a focus on best practices, testing, and long-term scalability - and you can architect, review, and debug complex systems with strong judgment.
A product-level thinker - you reason about users and outcomes, and you have opinions about what to build.
You believe the future of engineering is building systems that write code, and you already build this way - with real, hands-on experience using AI coding tools like Claude Code or Cursor. You don't need to be a master of it yet, but it shouldn't be new to you.
High agency, with a drive to keep improving your craft and to share what you learn with the team.
A collaborative mindset, able to work autonomously in a small, fast-paced team. Comfortable working in English.
Nice to have:
Experience with Python and/or machine learning.
Experience in renewable energy, drones/robotics, or another technical B2B domain. No solar background required - we'll teach you the domain; curiosity matters more.
Benefits
A team that moves fast, stays lean, and hires only the best.
Work on a mission that matters: accelerating the world's transition to renewable energy.
A competitive salary with fringe benefits.
Hybrid working model - two days a week in our Leuven office.