Senior Software Engineer I (Flex) in London

Location: London - Hybrid

Salary: £60,000 - £80,000

Team: Flex

Reporting to: Software Engineering Manager

At this time, we are not able to offer visa sponsorship for this role. We are committed to building a diverse, global team and our sponsorship policy is evaluated on a role-by-role basis. We encourage you to keep an eye on our careers site to stay informed about future opportunities where we are able to offer visa sponsorship.

Kaluza is the Energy Intelligence Platform, turning energy complexity into seamless coordination. We help energy companies overcome today's challenges while accelerating the shift to a clean, electrified future. Leveraging Data, AI, and real-time decision-making we turn energy complexity into growth opportunities for our partners.

By combining predictive algorithms with human-centred design, Kaluza makes clean energy dependable and affordable.

With teams across Europe, North America, Asia and Australia, and a joint venture with Mitsubishi Corporation in Japan, we power leading companies including OVO, AGL and ENGIE, as well as innovators like Volvo and Volkswagen.

What will I be doing?

You’ll be part of the Flex platform team, helping to build the systems that connect energy retailers, grid operators, and consumers to support a more flexible, dynamic energy system. Day to day, you’ll design and deliver scalable features, from integrating technologies like electric vehicles to enabling customer offerings such as 'Charge Anytime.' You’ll work closely with data scientists and backend engineers on core optimisation problems, while taking ownership of features from early idea through to ongoing improvement. Along the way, you’ll write high-quality, well-tested code and contribute to a strong engineering culture, building software that has a real impact on decarbonising transport and home energy use at scale.

About You

• Hands-on expertise in at least one programming language and experience contributing to a variety of complex systems.
• Strong knowledge of modern engineering practices, including continuous delivery, test automation, and agile methodologies.
• A passion for working in cross-functional teams to solve tough problems and build features that impact real customers.
• Motivation to own technical products throughout their entire lifecycle, focusing on continuous improvement and scalability.

What Will Set You Apart

• A genuine interest in the energy transition and developing products that positively impact the environment.
• Experience working across the full stack or with data-led optimisation engines in a high-scale environment.

Why might this role not suit you?

We are going through a period of significant evolution which is exciting and with it brings lots of opportunity and challenging work, which is not for everyone. To be successful in this role, you will be excellent at operating in ambiguous, changing environments, balancing multiple priorities simultaneously and get enjoyment from making the complex, simple.

Our Interview Process

• Initial Call with Talent Acquisition (30 minutes) - An introduction to Kaluza, the team, and your experience, with time to answer any initial questions.
• First Stage (1 hour) - A conversation with a hiring manager covering both technical topics and ways of working. This includes a short live coding exercise.
• Final Stage (3 hours total) - This stage includes three sessions, usually scheduled separately, though we can accommodate completing them in a single day if you prefer:

• Pairing - A collaborative session where you’ll work through a practical task with one of our engineers, focusing on problem-solving, clean code, and communication.
• System Design - Explores how you approach more complex problems, including designing scalable, reliable systems.
• Behavioural - Focuses on collaboration, problem-solving, and how you deliver value for customers, using real examples from your experience.

Kaluza Values

Here at Kaluza we have five core values that guide us as a business: Play to win, Solve the real problem, Build trust every day, Own the outcome, Go further together.

From us you’ll get:

• Pension Scheme
• Discretionary Bonus Scheme
• Private Medical Insurance + Virtual GP
• Life Assurance
• Access to Furthr - a Climate Action app
• Free Mortgage Advice and Eye Tests
• Perks at Work - access to thousands of retail discounts
• 5% Flex Fund to spend on the benefits you want most
• 26 days holiday
• Flexible working arrangements