Senior Full Stack Software Engineer in London

Are you passionate about securing the future of the planet by preventing catastrophic climate change? Do you want to apply your considerable creativity, energy, and digital expertise at the cutting edge of corporate climate action in one of the world’s fastest growing sustainability initiatives? The Science Based Targets initiative (SBTi) has an exciting opportunity for a Senior Full-Stack Software Engineer. Joining the growing digital function within the SBTi’s global operations team, you will collaborate closely with other teams to ensure that the SBTi technology infrastructure is well supported and service excellence is at the core of the organization.

About you: You have strong full-stack architecture skills and enjoy building efficient, scalable systems across the frontend and backend. You are highly structured and approach work strategically to build, deploy, and maintain robust web infrastructure using TypeScript, React, and Python. You are comfortable working with external specialists and seek effective ways to partner to ensure your work is fully realized and easily maintained. You take deep satisfaction in what you create and are motivated by delivering the right technical solutions to meet business needs. You thrive in a collaborative Agile environment where ideas and values are communicated clearly and respectfully. You are passionate about using your technical expertise to address climate change. English is the working language at SBTi, and the ability to communicate at a business‑fluent level is required.

About the SBTi: The Science Based Targets Initiative (SBTi) is a global body enabling businesses to set ambitious emissions reductions targets in line with the latest climate science. It is focused on accelerating companies worldwide to halve emissions before 2030 and achieve net‑zero emissions before 2050. The SBTi defines and promotes best practices in science‑based target setting, offers resources and guidance to reduce barriers to adoption, and independently assesses and approves companies’ targets.

Key Responsibilities:

• Collaborate closely & develop practices with DevOps by ensuring reliable deployment, monitoring, and scalability of applications across environments.
• Contribute to the day‑to‑day management of the SBTi website by working with subject matter experts to ensure content accuracy, relevance, and transparency.
• Design, implement, and maintain application code across the full stack using TypeScript, React, and Python in line with established standards.
• Contribute to the continuous improvement of digital platforms and performance to meet evolving user needs and business priorities.
• Modernise and refactor legacy codebases while ensuring system stability and functional continuity.
• Transform user stories and technical designs into high‑quality solutions that meet functional requirements and quality expectations.
• Develop and support robust, secure integrations between systems using REST‑based APIs and appropriate interface technologies.
• Write testable and maintainable code while supporting testing activities through defect resolution and root cause analysis.
• Support the stability of live services by investigating defects and contributing to fixes in line with agreed operational processes.
• Work closely with product and QA teams to deliver coherent solutions through active participation in backlog refinement and planning.
• Proactively improve development practices, AI‑assisted workflows, and knowledge sharing across the wider engineering team.

Experience and Skills:

• Google Cloud: Experience deploying and managing applications within the Google Cloud Platform (GCP) ecosystem.
• React: Expert knowledge of building interfaces, managing state, and optimizing performance within React.
• NodeJS/Express: Strong experience building and scaling server‑side applications using Express.
• Python Expert: Strong experience building backend services using FastAPI and managing database migrations with Alembic.
• AI Tooling: Familiarity with integrating AI APIs (such as Codex or Claude) and using AI‑assistant development workflows.
• Agile Experience: Proven track record working within Agile teams and participating in iterative delivery.
• Core Engineering: Proficiency in Git, REST API design, and modern CI/CD practices.
• Ability to work remotely and flexibly in a global environment with limited direct supervision; Strong written and oral communication skills, and advanced English level for non-native speakers.

Important information before you apply: This is a full‑time role based in the UK. The salary for this role will depend on location and experience level. Interested candidates should be legally allowed to work in the specified countries and already be visa holders. The SBTi cannot sponsor working visas. If you are interested, please complete our application form. Due to the high volume of applications we receive, only shortlisted candidates will be contacted. Thank you for your interest in SBTi.

What we offer:

• Working in one of the most successful and fastest‑growing initiatives driving climate action.
• Exciting and challenging tasks in a dynamic, international, innovative, and highly motivated team.
• Training and development.
• Attractive holiday package plus public holidays in your country.
• Competitive NGO salary range.

SBTi is an equal opportunity employer - committed to building an inclusive workplace and diverse staff, where all can thrive. We welcome and strongly encourage applications from candidates of all identities and backgrounds, and do not discriminate based on race, color, religion, gender or gender identity, sexual orientation, national origin, disability, or age.