Senior Full Stack Developer

Surphase · Donostia – San Sebastián · On-site

Permanent contract

€38,000-€48,000 gross/year

Minimum 4-5 years of experience

Build, Decide and Shape the future of the product

Are you excited by the idea of turning data into tools that solve real-world problems and help optimize industrial processes? At Surphase, we are looking for people who want to go beyond data analysis and actively contribute to building products with real impact.

We are a deep-tech startup born from the scientific community, currently in a key phase of industrialization and scale-up, looking for professionals who want to take real technical ownership of the product. We are not looking for execution alone. We value autonomy, product mindset and decision-making ability to bring together data, technology, and practical solutions that create measurable value for our customers.

Here, you will have clear visibility into the impact of your work, collaborate closely with multidisciplinary teams, and grow in an environment with strong professional development opportunities.

What will you find at Surphase

We know thatto achieve our goals, we need to provide an environment with conditions that measured up to our team.

- €38,000- €48,000 gross annual salary, with annual review linked to performance and objectives
- Technology project with real impact on sustainability, efficiency, and water treatment
- On-site work in Donostia | San Sebastián within a small, multidisciplinary, growing teaam
- Direct involvement in the evolution of the product
- Training plan and certification opportunities
- Professional growth as the technology area scales
- Adaptable hours and a short workday on Fridays and during the summer

Your mission in Surphase





You will be part of the team that is building and evolving our digital products and technology services. Your work will go beyond development: you will create internal tools, improve the user experience, and shape the layer that connects data, sensors, and people. You will help turn complex information into clear and useful solutions.

You will work alongside data, engineering, R&D;, and product teams to turn our technology into real value. You will create scalable solutions that help optimize processes and improve the way customers interact with our products.

What will you do?

- Design and evolve our architecture, ensuring scalability, maintainability, and long-term reliability
- Develop and maintain firmware for IoT devices
- Build and Integrate backend services, frontend applications, databases and APIs
- Connect sensor generated data with internal systems to enable analysis, visualizations and decision making
- Improve deployments, quality, monitoring, and scalability processes
- Document developments and integrations
- Identify opportunities for improvements, propose solutions, and take ownership of bringing them into production
- Python, FastAPI / Flask, REST APIs, Docker, JavaScript (CSS), SQL, NoSQL, GCP /Azure / AWS

Purpose

At Surphase, we believe that technology only makes sense when it creates a real impact.



We stand by the idea of driving progress in our society through our innovative and disruptive technology, which is why we work every day to achieve that goal. Our purpose is clear: to optimize the use of water resources through our innovative technology that detects membrane fouling, improving process efficiency and anticipating problems, and everything we do revolves around this.

That's why this role isn’t just about developing; it’s about turning complex technology into solutions that add value, improve processes, and have a tangible impact on our clients. Your work will directly contribute to that purpose, helping transform data, systems, and technology into useful, functional, and scalable tools designed for clients.

What we are looking for

We're not looking for a robot, but someone with interest, drive, and ambition to grow and develop with us. These are the qualities that would help in that process:

- 4-5 years of minimum experience as a Full Stack Developer or Senior Backend Developer
- On-site work in Donostia - San Sebastián
- Has designed and deployed end – to – end solutions
- Essential knowledge and experience developing in C
- Has a solid backend in Python + REST APIs and the ability to work in frontend developments
- Works with Docker, SQL, and cloud environments autonomously
- Ability to manage small, multidisciplinary work cells
- Can make technical decisions and propose solutions, not just execute specifications

Do we fit?

If you're looking for an environment where your work has a real impact, where you can get involved and build something real… This is your place. And us, your team.

Send us your CV and tell us about yourself

📌 Senior Full Stack Developer (San Sebastián)
🏢 Surphase
📍 San Sebastián