Backend Engineer

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.

We are looking for Backend Engineers (mid level) to join our Devices team and Low Carbon Tech team.

Devices:

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.

Low Carbon Tech:

Low Carbon Tech are installing EV Chargers, Solar, Batteries and Heat Pumps into homes to drive the energy transition at pace. As customer demand grows, our goal is to ensure scaling up never means slowing down or compromising on a world-class customer journey for low carbon tech. To make that happen, we are building a new, dedicated engineering and product team to completely re-imagine this process - making it fast, transparent, and predictable for our customers from day one.

You’ll help design and build the platform architecture, data integrations, and automations that eliminate real world friction. If you want to design and build solutions to scale up electrotech in the nation’s homes, 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.

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.

Requirements:

• 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.
• Coachable - genuinely interested in feedback and willing to adapt your approach.

Technologies:

• Python, Django
• PostgreSQL, Celery, and asynchronous background processing
• API architectures: GraphQL, REST, HTTP
• Domain modelling, writing fault-tolerant systems, and test-driven development (TDD)

Also valuable:

• TypeScript, AWS Lambda, CDK
• DynamoDB, event-driven microservices, API Gateway
• Distributed architecture and scaling across services

We would prefer someone who can work in our London office but will consider remote candidates. However, you do need to be able to work in the UK. Our process usually takes up to 4 weeks, but we’ll always do our best to flex around what works for you.

If this sounds like you then we'd love to hear from you. Studies have shown that some groups of people, like women, are less likely to apply to a role unless they meet 100% of the job requirements. Whoever you are, if you like one of our jobs, we encourage you to apply as you might just be the candidate we hire.

As an equal opportunity employer, we do not discriminate on the basis of any protected attribute. Our commitment is to provide equal opportunities, an inclusive work environment, and fairness for everyone.

Are you ready for a career with us? We want to ensure you have all the tools and environment you need to unleash your potential. Need any specific accommodations? Whether you require specific accommodations or have a unique preference, let us know, and we'll do what we can to customise your interview process for comfort and maximum magic!