Senior Software Engineer - Fullstack - Founding Team

☀️ Accelerating the Energy Transition, One Algorithm at a Time

TetraxAI is revolutionizing renewable energy infrastructure development, making it 100x faster and 10x cheaper through a cutting-edge B2B SaaS powered by AI.

Join our founding team of exceptionally experienced entrepreneurs :

Marta : Energy M&A lawyer with +2GW in transactions under her belt

Arnau : PhD in EECS, architected smart pricing algorithms at WalmartLabs

Katya : Launched Amazon Flex across 4 countries, scaling operations from scratch

Your Mission As a Founding Team member, you'll be responsible for designing, building and operating the software that will enable the processing of millions of documents and terabytes worth of project information every day, helping developers and investors make better decisions in a shorter time.

Core Responsibilities : Design, develop and operate our AI-agent powered document processing pipeline.

Maintain and operate our platform and its infrastructure with high availability.

Optimize & automate every single nook and cranny for high team efficiency.

Proactively propose & benchmark technical solutions to our customer’s business problems.

What We're Looking For Proven track-record of building scalable software solutions with data-heavy uses cases . We don’t care as much about years of experience but about wealth of experience in challenging situations and verticals.

Comfortable with trade-offs and with finding the right balance between best practices, debt and speed of execution on a case by case basis. We want folks that understand that there is no single best solution to all problems and that engineering is all about striking the right trade-offs.

Strong software architecture and system design fundamentals . With the advent of AI-tools that are proficient (and faster) at writing code, the role of designing the architecture and systems is more critical than ever. We want folks that have real-world knowledge of design patterns (and anti-patterns!).

Passion for our mission of fighting climate change with clean tech. Being a founding team member is an extremely challenging endeavor - believing in our mission is the (renewable) fuel that will power us through tough times.

Clear and rigorous communication . Building software at a startup is 90% communication (with stakeholders, with customers, with team members, with AI-assistants) to align, understand requirements and ideate an optimal solution. We are looking for engineers that enjoy collaboration and that understand that building complex systems is a team effort.

️ The TetraxAI Way At Tetrax, our culture is built around action, ownership, kindness and relentless focus on creating value for our customers . We’re a small, driven team solving hard problems—so how we work together matters just as much as what we’re building. These principles guide how we make decisions, collaborate, and grow :

Obsess Over the Customer : Our work starts and ends with the people we serve. We listen closely, ask questions, and design with empathy. If it doesn’t create value for our users, we don’t build it.

Act Fast, Learn Faster : We move quickly, experiment often, and don’t wait for perfect conditions. Progress beats perfection—and we learn by doing. Speed matters in business, especially when you’re building something new.

Own the Outcome : Everyone at Tetrax takes responsibility beyond their role. We don’t say “that’s not my job”—we dive in, take initiative, and follow through. We care deeply about the long-term success of what we’re building.

Deliver Results : Results matter. We set ambitious goals and hold ourselves accountable to them. We work with urgency, stay focused, and finish what we start—because impact only happens when ideas are executed.

Strive for Excellence : We take pride in the quality of our work. Whether it’s a product demo, a customer email, or a line of code—we push for high standards and constantly raise the bar for ourselves and each other.

Work with Integrity : We believe that how we work matters just as much as what we achieve. We treat others with respect, assume good intent, and communicate openly—even when it’s hard. We hold ourselves to high ethical standards and aim to create a culture where kindness, trust, and accountability go hand in hand.

Why Join Us? Impact : Your code will directly accelerate renewable energy project financing, contributing to global decarbonization efforts

Growth : Work directly with seasoned founders and gain hands-on experience in AI, energy, and climate tech

Compensation : €60-80k salary + top-of-market equity package.

Flexibility : Hybrid work model in beautiful Barcelona, 2.5-day / week in-person

‍‍‍  Family-friendliness : We have children and understand that even though this is a startup, first things come first.

Flat-hierarchy : we encourage open communication, fast decision-making, and mutual respect. You’ll work directly with the founding team and have real ownership over your projects.