Fullstack, backend-leaning · London (hybrid) · Full-time · Founding-level IC · Meaningful equity

⚡️ About Volter

Volter is a top-tier climate VC-backed B2B energy supplier and technology platform, building the products that make clean, renewable power simple for businesses. The energy transition is a huge and vital opportunity, but for commercial & industrial companies it is still too opaque, too complex and too hard to trust. We're fixing that.

Our aim is to be the "Octopus Energy for industry": an AI-native supplier built on our own modern platform, providing renewable energy products with radical transparency, accelerating the deployment of renewables and helping customers cut cost and carbon without complexity. We are a supplier first, then a platform: prove the tech by running an excellent supply business on it, then open it up to others.

💼 The role

This is the most senior individual-contributor engineering role at Volter. You will work directly with our most senior Engineers and founders to own the architecture and technical direction of the core supply platform: the systems that price, contract, meter, settle and bill energy for our customers, and the product surfaces our customers and internal teams use every day.

You are fullstack but your centre of gravity is the backend: services, domain modelling, APIs, reliability. You will ship code most days, but your impact is measured by what the whole team ships. You raise the bar on how we design, build and operate software, you take on the gnarliest problems, and you make everyone around you better.

You dislike bureaucracy and believe in a "best idea wins" culture. You have done the big-company or scale-up thing and know what good looks like, and now you want the leverage of building it from the beginning, in a flat, growth-oriented team where your judgement shapes the company.

🛠️ What you'll own

• Architecture and technical direction for the supply platform: billing, pricing, contracting, settlement and meter-data domains. Decide what we build vs. buy, what we build now vs. later, and how the pieces fit together as we scale from tens to thousands of sites.
• Design, build and run backend services and APIs in Go and Python: robust domain models, event-driven workflows, background jobs, integrations with market and industry counterparties.
• Ship end-to-end product features, including key front-end flows in TypeScript/React, so customers and ops teams get working software in days, not weeks.
• Set and hold engineering standards: testing, CI/CD, observability, security-by-default, privacy, cost and performance. Own the practices that let a small team move fast without breaking things that bill customers real money.
• Multiply the team: design reviews, pairing, mentoring, hiring. Grow our engineers and help us hire the next ones. Set the tone for how we use AI tooling to build faster and better.
• Partner with commercial, product and ops to turn messy real-world energy problems into simple, well-scoped systems, and push back when the simple version is the right one.

🧩 What you bring

• 10+ years building and operating production software, with at least a few of them at staff, principal or tech-lead level on systems other people depended on.
• Deep backend expertise: distributed systems, API and domain design, transactional correctness, idempotency, failure modes. You have built systems that move money or data that must be right, and you have the scars.
• Strong across the stack: fluent in Go and/or Python on the backend and comfortable owning a TypeScript/React front end. You would rather ship the whole feature than hand half of it over the wall.
• Sound data fundamentals: schema design, query optimisation, and modelling for time-series, transactional and analytical needs. Comfortable in Postgres and adjacent tooling; no data-platform experience required.