Backend Engineer in London

Octopus Energy started with a bold idea: to build Britain's first truly digital energy supplier.

By combining world-class tech with brilliant humans who care deeply about customers and driving the renewable energy transition, we made it happen and in 2025, we became Britain's largest energy supplier.

Now, we're scaling fast and building the next generation of products to accelerate the green energy transition.

From making it effortless to switch to heat pumps, solar and EVs, to launching smart tariffs and creating renewable generation at scale, we're solving some of the most complex challenges in energy with speed, creativity and customer obsession.

We're also enabling our global businesses to reach the full capability of what we've achieved in the UK, taking the learnings, products and experiences that customers love here and rolling them out worldwide.

At Octopus Tech, you'll have real ownership, variety, and the chance to shape products that make a tangible difference in people's lives - lowering bills, enabling greener living, and delivering experiences customers genuinely love.

You'll work side by side with teams across marketing, operations, and data, and see the impact of your work in the real world, fast.

We are looking for a Backend Engineer II to join our Devices team.

Since launching our first piece of hardware, Home Mini, in 2022, followed by Cosy Heat Pumps in 2023 and the Charge EV Charger in 2025, we have continued to expand our portfolio of devices, helping customers make the green energy transition.

You’ll join a cross-functional team of backend and mobile engineers, working closely with our hardware team to extend and improve integrations for both existing and new devices in the Octopus Energy app.

This includes the recently announced Nook family of home batteries, with more exciting products already in the pipeline.

If you want to design and build solutions that scale low-carbon technology in homes across the UK, this is the mission for you.

We embrace flat hierarchies and an open, agile culture that fosters innovation, flexibility, and creativity.

We don't hang our personalities up with our coats and nor should you. At Octopus, we hire great people who get stuff done, all whilst being themselves.

If this sounds exciting, we'd love to chat.

What you'll do

• Take independent ownership of medium-sized technical features and components, delivering stable and production-ready code with minimal supervision.
• Ship continuously to trunk - small PRs, fast feedback, no release trains. You'll be working in a codebase with ~100 merges per week from dozens of contributors.
• Build and extend a Django backend serving multiple countries from a single codebase, making deliberate decisions about what should be generic vs. territory-specific.
• Integrate with upstream platform services (Kraken Customer, Kraken Field, Kraken Flex) that provide billing, CRM, auth, and device control - orchestrating across service boundaries daily.
• Proactively identify and address monitoring, alerting, and observability gaps within your applications to ensure live systems run predictably.
• Engage confidently in feature technical designs, participate actively in code reviews, and provide clear documentation for your pull requests.
• Use systematic, structured approaches to resolve bugs or service blockers, and confidently step in to address incident management within your core domain.
• What you’ll need
• Solid backend foundations with a 3-4 year track record building web applications in Python, ideally with Django.

Experience writing highly testable code (unit, integration, and functional tests run in parallel in CI) and working with relational databases and background task processing.

• Comfortable working in a large, multi-tenant codebase - navigating and extending shared abstractions, territory-specific behaviour, and integrations with upstream services.

The habit of asking "would this work for another territory?" before building something bespoke.

• Comfortable with pace over process - we ship continuously, not in sprints, and trust automated guardrails (type checking, linting, CI) over manual gates.
• Openness and excitement around integrating modern AI tools into daily development, testing, and debugging to maintain pace and spark innovation.
• High initiative - able to break down engineering problems into shippable slices and make steady progress when requirements are evolving or domain context is still being built.
• A genuine curiosity about smart energy devices and the technology that connects them to people's homes.

You won't need hardware expertise, but you'll be building the software that makes these devices useful to customers.

• Coachable - genuinely interested in feedback and willing to adapt your approach.
• Our core tech stack… Python, Django
• Postgre SQL, Celery, and asynchron
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