Application Guide

How to Apply for Senior Backend Engineer

at Octopus Energy

🏢 About Octopus Energy

Octopus Energy is a disruptor in the energy sector, leveraging AI and renewables to drive transparency and a low-carbon future. Their flat hierarchy and agile culture make it an exciting place for engineers who want to directly impact the energy revolution.

About This Role

As a Senior Backend Engineer, you will build and maintain critical services for customer-facing platforms, including time-of-use tariffs and meter reading features. Your work will directly support Octopus Energy's mission to make energy smarter, greener, and more affordable.

💡 A Day in the Life

Start with a stand-up with your distributed team, then dive into coding a new GraphQL endpoint for tariff management. After lunch, you'll review a colleague's PR on Celery task optimization and later pair program on a Postgres migration. The day ends with a cross-team sync on integrating with smart meter APIs.

🎯 Who Octopus Energy Is Looking For

  • Deep experience with Python and Django, having built and scaled production systems handling high concurrency and fault tolerance.
  • Expert in domain modeling and GraphQL, with a track record of designing clean, maintainable APIs.
  • Proficient with Celery, async processing (e.g., asyncio), and PostgreSQL optimization.
  • Bonus if you have AWS cloud experience (e.g., Lambda, ECS) or React/Next.js with TypeScript for full-stack collaboration.

📝 Tips for Applying to Octopus Energy

1

Highlight your experience with time-of-use tariff logic or similar real-time pricing models.

2

Showcase any open-source contributions or side projects that demonstrate your passion for clean energy or sustainability.

3

In your resume, quantify impact: e.g., 'Optimized Celery task processing, reducing latency by 30%'.

4

Mention cross-team collaboration in a remote or multi-country setting.

5

Tailor your cover letter to Octopus Energy's mission: emphasize how your backend work can help reduce CO2 emissions.

✉️ What to Emphasize in Your Cover Letter

["Your motivation for working in the energy sector and alignment with Octopus's mission.", 'Specific examples of building robust, fault-tolerant distributed systems with Python/Django.', 'Experience with GraphQL and domain modeling in complex domains.', 'Your ability to work autonomously in a remote, flat-hierarchy environment.']

Generate Cover Letter →

🔍 Research Before Applying

To stand out, make sure you've researched:

  • Read Octopus Energy's blog posts on their tech stack and engineering culture (e.g., Kraken platform).
  • Understand the UK and US energy markets, especially time-of-use tariffs and smart meters.
  • Check out Octopus's public GitHub repositories or tech talks.
  • Look into their AI initiatives, such as using ML for energy demand forecasting.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Design a time-of-use tariff backend system: how would you model tariffs, handle meter readings, and ensure correctness?
2 How do you handle async tasks in Celery? Discuss error handling, retries, and monitoring.
3 Explain your approach to domain modeling for a multi-tenant energy platform.
4 Describe a time you optimized a PostgreSQL query or schema for performance.
5 How would you ensure fault tolerance in a service that processes real-time meter data?
Practice Interview Questions →

⚠️ Common Mistakes to Avoid

  • Don't submit a generic application; research Octopus's specific tech and mission.
  • Avoid focusing solely on frontend or non-Python experience if you lack backend depth.
  • Don't ignore the 'fault-tolerant' requirement; be ready to discuss distributed systems patterns.

📅 Application Timeline

This position is open until filled. However, we recommend applying as soon as possible as roles at mission-driven organizations tend to fill quickly.

Typical hiring timeline:

1

Application Review

1-2 weeks

2

Initial Screening

Phone call or written assessment

3

Interviews

1-2 rounds, usually virtual

Offer

Congratulations!

Ready to Apply?

Good luck with your application to Octopus Energy !