Senior Full Stack Engineer

Change the World, Bit by ByteAt T4G Lab, we are more than just a tech consultancy. We are partners in impact. We build technology that matters. We work with startups, non-profits, universities and United Nations to solve real-world problems in Health, Climate Change, Education, Research or Financial Access. We are looking for a seasoned Full Stack Engineer with deep experience to join our global team. You will build scalable, high-impact solutions that empower organisations to move faster and do more good.The RoleAs a Senior Member of our engineering team, you will be hands-on in designing, building, and deploying robust applications. You won’t just be writing code. You will be crafting solutions for complex challenges, ensuring our partners get world-class, secure, and sustainable products. This is a pure Full Stack role where you will own features from the database to the UI, but with a heavy emphasis on architectural soundness and infrastructure security.What You’ll DoBuild & Scale: Develop high-quality, maintainable software across the full stack (Frontend + Backend).Secure Infrastructure: Take ownership of cloud architecture. You will ensure our systems are not just functional but are secure by design and optimised for performance.Impactful Work: Work on diverse projects ranging from AI integration to lean product adjustments for startups and non-profits.Mentor & Lead: Use your experience to set coding standards and mentor other developers in the team.Collaborate: Work directly with founders, product managers, and non-technical stakeholders to translate "vision" into "shipped code."Who You AreExperienced: You have 8+ years of professional experience in software engineering. You have seen it all, including legacy code, greenfield projects, and complex migrations.Fluent in English: You have excellent written and verbal communication skills in English. As a global consultancy, clear communication with international partners is essential.Tech Versatile & Secure: You go beyond just writing features.Strong Backend & Frontend skills (Python/Django and React preferred, but we value solid engineering fundamentals).Infrastructure Mastery: You have strong knowledge of cloud infrastructure (AWS), DevOps, and deployment pipelines.Security First: You understand OWASP top 10, data encryption, and secure authentication practices. You build systems that protect user data.AI/LLM Proficiency: Experience with AI coding tools and techniques for integrating LLMs into the development process is highly desirable.Problem Solver: You care about solving the problem rather than just using the flashiest new tool. You understand how to build lean and efficient solutions.Nice to Have (But Not Required)Language Skills: Proficiency in Spanish or other UN official languages is a great asset.Accessibility Expert: You know how to build inclusive web experiences that meet WCAG standards.Sustainable Tech: You have knowledge or interest in "Green IT" and sustainable hosting practices to minimise carbon footprint.Why Apply?Meaningful Work: Your code will directly support impactful projects in sectors that change lives.Global Mindset: Work with a diverse, international team and partners worldwide.Senior Impact: At your level, your voice matters. You will help shape technical strategy and team culture.Remote/Flexible Culture: We focus on output and impact rather than hours in a chair.Ready to join us in changing the world, bit by byte? Click Easy Apply today.

Experienced: You have 8+ years of professional experience in software engineering. You have seen it all, including legacy code, greenfield projects, and complex migrations. Fluent in English: You have excellent written and verbal communication skills in English. As a global consultancy, clear communication with international partners is essential. Tech Versatile & Secure: You go beyond just writing features. Strong Backend & Frontend skills (Python/Django and React preferred, but we value solid engineering fundamentals). Infrastructure Mastery: You have strong knowledge of cloud infrastructure (AWS), DevOps, and deployment pipelines. Security First: You understand OWASP top 10, data encryption, and secure authentication practices. You build systems that protect user data. AI/LLM Proficiency: Experience with AI coding tools and techniques for integrating LLMs into the development process is highly desirable. Problem Solver: You care about solving the problem rather than just using the flashiest new tool. You understand how to build lean and efficient solutions. Nice to Have (But Not Required) Language Skills: Proficiency in Spanish or other UN official languages is a great asset. Accessibility Expert: You know how to build inclusive web experiences that meet WCAG standards. Sustainable Tech: You have knowledge or interest in "Green IT" and sustainable hosting practices to minimise carbon footprint.

Barcelona, España

Change the World, Bit by Byte At T4G Lab, we are more than just a tech consultancy. We are partners in impact. We build technology that matters. We work with startups, non-profits, universities and United Nations to solve real-world problems in Health, Climate Change, Education, Research or Financial Access. We are looking for a seasoned Full Stack Engineer with deep experience to join our global team. You will build scalable, high-impact solutions that empower organisations to move faster and do more good., Why Apply? Meaningful Work: Your code will directly support impactful projects in sectors that change lives. Global Mindset: Work with a diverse, international team and partners worldwide. Senior Impact: At your level, your voice matters. You will help shape technical strategy and team culture. Remote/Flexible Culture: We focus on output and impact rather than hours in a chair. Ready to join us in changing the world, bit by byte? Click Easy Apply today.