At a Glance
- Tasks: Lead a team to develop scalable back-end services for our innovative grid modelling platform.
- Company: Join a passionate climate-tech startup dedicated to advancing the energy transition.
- Benefits: Enjoy flexible working, competitive salary, and generous leave policies.
- Other info: Diverse and inclusive culture with excellent career growth opportunities.
- Why this job: Make a real impact in the energy sector while working with cutting-edge technology.
- Qualifications: 7+ years in back-end development, strong Python skills, and experience with cloud platforms.
The predicted salary is between 70000 - 90000 £ per year.
You should have a long-term commitment to advancing the energy transition and be driven to build robust, scalable systems that power our grid modelling platform. Passionate about creating highly performant back-end services, you understand the technical challenges associated with building niche B2B products that handle complex computational workloads. In addition to seeking out people with a proactive, problem-solving attitude and an eye for detail, as a growing organisation, collegiality and empathy for our coworkers are a requisite. While we are a rapidly growing tech startup, we are also a non-profit, so a high level of adaptability and willingness to approach challenges with creativity and curiosity is essential.
About the role: You will line-manage a small team of engineers while remaining a highly active individual contributor. You will own the technical shape of engineering work on the back-end team — leading planning, architecture, and code quality. You will work closely with the wider product and engineering team to design, develop, and maintain the back-end services that power our platform. This hybrid role is based out of our London office near Waterloo Station and reports to the Head of Platform.
Responsibilities
- Back-end development & architecture: 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.
- Infrastructure & DevOps: 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.
- Technical leadership & collaboration: 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.
- People & line management: 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.
Skills and experience
- 7+ years of experience in back-end software development, with strong proficiency in Python.
- Experience designing and building RESTful APIs and microservices architectures.
- Strong understanding of database technologies (PostgreSQL, Redis, Firestore), ORMs and data modelling principles.
- Experience with cloud platforms (preferably GCP) and containerisation technologies (Docker).
- Solid understanding of software engineering best practices, including testing, code review, and documentation.
- Excellent problem-solving skills and ability to work independently on complex technical challenges.
- Experience line managing or formally mentoring engineers, with confidence running 1:1s and supporting career development.
- Understanding of OAuth and web security best practices.
- Experience with AGILE/Scrum based ways-of-working.
- Experience in the energy sector or with computational modelling/simulation software.
- Familiarity with scientific computing libraries (NumPy, Pandas) and optimisation frameworks.
- Experience with generative AI/LLMs in applied engineering contexts.
- Experience with infrastructure-as-code tools (Terraform, Terragrunt) and GitOps practices.
About us
We are a climate-tech startup established in 2021. We provide electricity grid modelling software to accelerate energy planning in emerging markets and developing economies. Today’s tools are costly, closed, and hard to use, with modelling studies taking months or years when they should take weeks or days. We designed Scenario Builder to meet this challenge, so energy planners and investors can make better decisions, faster.
Our funding currently comes from a range of US and EU foundations, including the Quadrature Climate Foundation, Google.org, the Sequoia Climate Foundation, Bloomberg Philanthropies, and the European Climate Foundation. At TransitionZero, we understand that diversity is an essential component of a successful team, whether that be diverse ways of thinking, personal or professional backgrounds, or skills. We aim to be the most talented non-profit in our vertical through our culture of ownership and adaptability.
Enhanced competitive pension scheme - auto-enrollment from day 1, 25 days annual leave (excluding UK public holidays) and additional discretionary days off such as over the festive period, 20 days of annual allowance to work from anywhere in the world, hybrid working and core working hours model, allowance to set up your home office, annual budget and dedicated leave time for relevant training courses, enhanced gender-neutral parental leave (16 weeks fully paid), private healthcare following the successful completion of the probation period, yearly team offsites.
Our commitment to diversity, equity, and inclusion
Studies have shown that some people from marginalised or underrepresented groups are less likely to apply to a role unless they meet all of the hiring guidelines or qualifications. Whoever you are, even if you don’t meet all of the criteria, if you can demonstrate a variety of skills and experience relevant to this role, we encourage you to apply as you might just be the candidate we hire! At TransitionZero, we’re looking for people who are genuinely passionate about what they do, and we welcome all people, regardless of their background.
If you would like to discuss any reasonable adjustments to the application or hiring process that may better facilitate your participation, please contact our People Team (people@transitionzero.org) for an informal chat. We will make every effort to respond to your request for assistance as soon as possible.
Principal Software Engineer employer: TransitionZero
TransitionZero is an exceptional employer for those passionate about advancing the energy transition through innovative technology. Located in London, our hybrid work model promotes a healthy work-life balance, while our commitment to employee growth is reflected in our generous training budgets and supportive line management. With a culture rooted in diversity, empathy, and collaboration, we empower our team to tackle complex challenges in a meaningful and rewarding environment.
StudySmarter Expert Advice🤫
We think this is how you could land Principal Software Engineer
✨Tip Number 1
Network like a pro! Reach out to folks in the industry, attend meetups, and connect with people on LinkedIn. You never know who might have the inside scoop on job openings or can put in a good word for you.
✨Tip Number 2
Show off your skills! Create a portfolio or GitHub repository showcasing your projects, especially those related to back-end development and APIs. This gives potential employers a taste of what you can do and sets you apart from the crowd.
✨Tip Number 3
Prepare for interviews by practising common technical questions and coding challenges. Brush up on your Python skills and be ready to discuss your experience with cloud platforms and microservices. Confidence is key!
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen. Plus, we love seeing candidates who are genuinely interested in our mission to advance the energy transition.
We think you need these skills to ace Principal Software Engineer
Some tips for your application 🫡
Show Your Passion:When writing your application, let your enthusiasm for the energy transition shine through. We want to see that you're not just looking for a job, but that you're genuinely excited about making a difference in this field.
Tailor Your Experience:Make sure to highlight your relevant experience in back-end development and any specific projects that relate to our grid modelling platform. We love seeing how your skills align with what we do, so don’t hold back!
Be Clear and Concise:Keep your application straightforward and to the point. We appreciate clarity, so avoid jargon and focus on communicating your ideas effectively. Remember, less is often more!
Apply Through Our Website:We encourage you to submit your application directly through our website. It’s the best way for us to receive your details and ensures you’re considered for the role. Plus, it’s super easy!
How to prepare for a job interview at TransitionZero
✨Know Your Tech Inside Out
Make sure you’re well-versed in Python and the frameworks mentioned, like FastAPI. Brush up on your knowledge of RESTful APIs and microservices architectures, as you'll likely be asked to discuss your experience with these during the interview.
✨Showcase Your Problem-Solving Skills
Prepare to share specific examples of complex technical challenges you've faced and how you tackled them. This role requires a proactive attitude, so demonstrating your problem-solving approach will really impress the interviewers.
✨Emphasise Team Collaboration
Since this position involves line management and collaboration with cross-functional teams, be ready to talk about your experience in leading teams and working with others. Highlight any instances where you’ve successfully managed team dynamics or resolved conflicts.
✨Adaptability is Key
As a growing non-profit startup, adaptability is crucial. Be prepared to discuss how you've approached challenges creatively and how you can bring that mindset to their team. Showing your willingness to learn and adapt will resonate well with the interviewers.
