Senior Backend Engineer - Low Carbon Tech (LCT)

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 our services business, making it easy to switch to heat pumps, solar and EVs, and launching smart tariffs for Low Carbon Tech.
With this, we’re also taking the learnings, products and experiences that customers love here and rolling them out worldwide.
OE Tech is the engineering and product organisation inside Octopus Energy. Here 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 services, marketing, operations, and data, and see the impact of your work in the real world, fast.
We are looking for a Senior Backend Engineer to join our Low Carbon Tech team. 
We 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. This will be a small multi-disciplinary team who’ll sit within our much bigger low carbon tech team.
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.

What you'll do...

• Take total technical ownership of key platform components, shaping direction and bringing clarity to ambiguous problems while ensuring solutions are well-designed, scalable, and maintainable.

• Consistently write production-ready, self-documenting code that requires minimal revision, and actively improve testing strategies, non-functional requirements (performance, security, scale), and test infrastructure.

• Tackle systemic bottlenecks and architectural risks across multi-service configurations before they hit production, utilising highly systematic debugging approaches.

• Mentor other engineers, lead technical discussions, and perform rigorous code reviews to leave our systems, practices, and people stronger than you found them. Your influence will go far beyond your own delivery to help make Octopus an incredible place to be an engineer.

What you'll need...

• 5+ years experience of robust backend development with deep expertise in systems design, database optimisation (PostgreSQL/MySQL), and cloud execution.
  
• Excited by the possibilities of integrating AI tools into your workflow to iterate quickly, combined with the discipline to rigorously check and ensure code quality.
  
• Clear communication skills, with a proven ability to translate complex technical constraints and architectural risks cleanly to non-technical stakeholders (compliance, operations, business development).
  
• A genuine curiosity about the green technology landscape. You won't be expected to dive into physical engineering or device-level software, so you don't need to be a hardware expert, we’re just looking for someone who shares our passion for getting clean energy into millions of homes.

Our Tech Stack...

Python, Django

PostgreSQL, Celery, and asynchronous background processing

API Architectures HTTP, REST APIs, GraphQL

Domain modeling, writing fault-tolerant systems, and test-driven deployment (TDD)

AWS, Terraform, Packer, Consul, microservices, and distributed architecture scaling

💚Why else you'll love it here...

💰 Wondering what the salary for this role is? Just ask us! On a call with one of our recruiters it's something we always cover as we genuinely want to match your experience with the correct salary. The reason why we don't advertise is because we honestly have a degree of flexibility and would never want salary to be a reason why someone doesn't apply to Octopus - what's more important to us is finding the right octofit!
🎉 Octopus Energy Group is a unique culture. An organisation where people learn, decide, and build quicker. Where people work with autonomy, alongside a wide range of amazing co-owners, on projects that break new ground. We want your hard work to be rewarded with perks you actually care about! We won best company to work for in 2022, on Glassdoor we were voted 50 best places to work in 2022 and our Group CEO, Greg has recorded a podcast about our culture and how we empower our people. We’ve also been placed in the top 10 companies for senior leadership
🎁 Visit our UK perks hub - Octopus Employee Benefits