Full Stack Engineer

everyone to innovate. We’re based in Barcelona and work primarily from the office, because the energy of working side by side matters to us. About This Position Tree-Nation has a platform, a database, running integrations, and active business units. You’ll join a small, high-ownership tech team building and maintaining the Tree-Nation platform - the web app, the mobile app, the B2B tooling, the planting flows, and the integrations that tie it all together. This means backend services, APIs, data models, and the frontend interfaces that users and internal teams interact with. The team works without heavy process layers: you’re expected to understand the product deeply, make good technical decisions, and take ownership of what you ship. You’ll work closely with the rest of the engineers and directly with the people running the business, which means your work has a visible impact from day one. What You’ll Do - Build and maintain features across the Tree-Nation web platform (Vue.js +

PHP) and mobile app (React Native) - frontend and backend, depending on where the work is. - Design and implement backend services, APIs, and database schemas that are clean, modular, and built to last. - Collaborate with the rest of the tech team on architecture decisions, code reviews, and technical problem-solving. - Diagnose before you build - map existing workflows, identify what’s fragile or manual, and define system scope precisely before writing a line of code. - Own features end-to-end: design the data model, build the backend service, expose the API, and ship the frontend interface that makes it usable - without throwing work over a wall. - Prototype fast, then industrialize - using whatever stack solves the problem. Our backend is PHP, our frontend is Vue.js, and we also use TypeScript - but we don’t have a sacred stack. - Own observability and failure handling from day one, not as an afterthought. - Use AI tools actively in your workflow - to prototype faster, improve code quality, and identify automation opportunities within your domain. What You’ll Bring Required - Strong full-stack background - you’ve shipped production systems on both frontend and backend and you’re genuinely comfortable on both sides. - Deep database design thinking: you model data before you write code and understand how schema decisions propagate into downstream behavior. - Experience with modular service architecture - systems that are scoped, isolated, composable, and replaceable. - Solid system design instincts: APIs, state management, integration patterns, failure handling, and observability. - Genuine full-stack experience: solid backend skills (PHP, RESTful APIs, database design) and confident frontend work (Vue.js, building interfaces that are actually pleasant to use). - Tool-agnostic approach - you choose the right tool for the problem and are comfortable building custom when off-the-shelf doesn’t fit. - You diagnose before you prescribe - the right solution starts with the right question, and you can sit with ambiguity long enough to understand a problem fully before proposing a fix. - Based in Barcelona and comfortable working on-site. Nice to Have - Experience with React Native - our mobile app is built on it, and any familiarity is a head start. - Practical exposu

About Tree-Nation Tree-Nation is the world’s largest reforestation platform, connecting citizens and companies with verified planting projects across the globe. Since 2006, over 800,000 users and 30,000+ companies have planted more than 45 million trees through our platform, across 40+ active reforestation projects worldwide. We combine technology and environmental impact to make reforestation simple, transparent, and scalable. Our goal is to plant 1 trillion trees by 2050 and we’re building the platform, the automation, and the systems to get there. The Team - What We Are Made Of Our team spans many nationalities, backgrounds, and disciplines. What we share is a mindset: we take ownership because we care about what we’re building, we don’t back down from hard problems, and we trust each other to lead, make decisions, and ask for help when needed. We are investing heavily in automation and AI to scale our impact. The company provides access to the latest LLMs, and we strongly encourage