Staff Engineer (Global Billing, Payments & API)

About the Position

Kaluza is seeking a Staff Engineer (Global Billing, Payments & API) to join their engineering team in London, Bristol, or Edinburgh. This role is pivotal in building and evolving the platform that underpins billing and payments capabilities for some of the world's largest energy retailers.

Responsibilities

• Own system design and architecture for the API Platform and Standards squad.
• Create and challenge product and engineering proposals, backed by data.
• Diagnose and resolve complex technical and product issues.
• Establish architectural patterns and technical standards for other teams.
• Turn ambiguous, loosely-defined technical requirements into concrete plans.
• Influence engineering leadership, product, and adjacent squads on technical direction.
• Mentor and upskill engineers, fostering a wider learning culture.

Requirements

• Deep technical expertise in system design and architecture.
• Ability to create and challenge proposals, backed by data.
• Track record of diagnosing and resolving complex technical and product issues.
• Skilled at establishing and driving adoption of architectural patterns and technical standards.
• Comfortable with ambiguous, loosely-defined technical requirements.
• Accomplished at influencing both upwards and outwards.
• Experience mentoring and upskilling other engineers.
• Comfortable operating in a high-integrity data domain.
• Demonstrable customer obsession and a working-backwards practice.
• Record of applying AI/LLMs to deliver customer impact.

Nice to Have

• Direct experience with API gateway, versioning, or developer-experience standards work at scale.
• Direct experience in billing, payments, or financial-services domains.
• Experience operating a "global core, configurable edge" or multi-market platform model.

We Offer

• Competitive salary: £97,000 - £122,000
• 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
• Progressive Leave Policy - Including 26 weeks full pay for new family additions
• Personal Learning Budget - Upskill, learn and grow!
• Home Office Budget

About the Company

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. Our platform orchestrates millions of real-time decisions across homes, devices, markets, and grids. By combining predictive algorithms with human-centred design, Kaluza makes clean energy dependable, affordable, and adaptive to everyday life.

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.

Kaluza Values

• Play to win
• Solve the real problem
• Build trust every day
• Own the outcome
• Go further together

Where You'll Work

We offer flexible working, with an expectation of 3 days a week in the office. This gives us the best of both: real-time collaboration and the flexibility to work in the way that suits you best the rest of the week.

We Want the Best People

We’re keen to meet people from all walks of life - our view is that the more inclusive we are, the better our work will be. We want to build teams which represent a variety of experiences, perspectives, and skills, and we recognize talent on the basis of merit and potential. If you're excited about joining us and think you have some of what we're looking for, even if you're not 100% sure, we'd still love to hear from you.

Find out more about working in Kaluza on our careers page and LinkedIn.