Lead Engineer (Back-End)

TransitionZero is a climate tech non-profit founded in 2021, focused on building software to facilitate clean energy development. They are seeking an experienced Lead Engineer (Back-End) to lead the engineering team in building and scaling the infrastructure for their electricity grid modelling platform, Scenario Builder, while managing a small team and ensuring high-quality back-end services.

Responsibilities:

• Design, develop, and maintain scalable back-end services and APIs using Python and modern frameworks (FastAPI)
• Design and build high-performance API endpoints to handle complex hierarchical data queries and multi-dimensional aggregations for grid modelling computations
• Ensure system reliability, performance, and security through best practices in code quality, testing, and monitoring
• Collaborate with front-end engineers to design and implement RESTful APIs that support our web application
• Collaborate with data engineers and domain experts on the evolving core data model
• Manage and optimise cloud infrastructure (GCP) to support our computational workloads
• Implement and maintain CI/CD pipelines to enable rapid, reliable deployments
• Monitor system health and performance, proactively identifying and resolving issues
• Implement and maintain infrastructure-as-code
• Participate and lead in code reviews, architectural discussions, and technical planning sessions
• Own technical planning: break down roadmap items into well-scoped engineering work, lead estimation, and drive architectural decision records (ADRs)
• Collaborate with cross-functional teams, including product, data engineering, and modelling, to deliver impactful features
• Set and uphold the team's technical standards — code quality, testing strategy, API design — through direct example and code review
• Line-manage a team of 3–5 engineers: run regular 1:1s, support career development, and provide timely, constructive feedback
• Partner with the Head of Platform on performance reviews and personal development plans
• Act as the first point of escalation for day-to-day technical blockers