Application Guide

How to Apply for Backend Engineer

at Octopus Energy

🏢 About Octopus Energy

Octopus Energy is redefining the energy sector by combining transparency, AI, and renewable energy to drive a low-CO2 future. Their agile culture, flat hierarchies, and focus on innovation make them a standout employer for engineers who want to make a tangible impact on climate change.

About This Role

As a Backend Engineer, you'll own key product modules like bill management and customer onboarding, working across international teams to deliver features that directly affect millions of customers. This role offers rapid feedback cycles and the chance to drive fast-paced impact in a mission-driven company.

💡 A Day in the Life

Start your day with a standup with the Spanish and UK teams, then dive into coding a new billing feature. You'll review a GraphQL schema design, debug a Celery task, and end the day by deploying a hotfix that improves customer onboarding flow.

🎯 Who Octopus Energy Is Looking For

  • Experienced Python developer with deep Django knowledge, comfortable building scalable backend services.
  • Strong in GraphQL and REST API design, with a track record of integrating complex systems.
  • Proficient in Celery and async task processing, plus relational databases (PostgreSQL preferred).
  • Proactive problem-solver who thrives in agile, flat-hierarchy environments and takes ownership of modules.

📝 Tips for Applying to Octopus Energy

1

Highlight specific Django projects where you owned a module end-to-end, including database schema and API design.

2

Showcase your experience with GraphQL by providing a link to a public API or describing a complex query optimization.

3

Mention any work with Celery or async tasks, especially in handling large-scale batch processing or real-time updates.

4

Tailor your resume to emphasize energy or sustainability projects, even if personal or open-source.

5

In your cover letter, explicitly connect your past work to Octopus's mission of transparency and low CO2.

✉️ What to Emphasize in Your Cover Letter

["Your passion for renewable energy and how your backend skills can directly contribute to Octopus's mission.", 'Experience with fast-paced, agile environments and taking ownership of critical product modules.', 'Technical expertise in Python, Django, GraphQL, and Celery, with concrete examples of scalable solutions.', 'Ability to collaborate across time zones and cultures, as the role works with global teams.']

Generate Cover Letter →

🔍 Research Before Applying

To stand out, make sure you've researched:

  • Read Octopus Energy's blog on their tech stack and how they use AI for energy forecasting.
  • Understand their 'Kraken' platform and how it integrates with global energy markets.
  • Check their sustainability reports to see how they measure CO2 reduction impact.
  • Explore their open-source contributions or public APIs to understand their engineering culture.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Design a scalable billing system for millions of customers using Django and Celery.
2 Explain how you would optimize a slow GraphQL query with nested relationships.
3 Describe a time you handled a production incident and improved system reliability.
4 How would you model customer onboarding data to support both web and mobile apps?
5 Discuss your approach to testing and ensuring fault tolerance in distributed systems.
Practice Interview Questions →

⚠️ Common Mistakes to Avoid

  • Ignoring the mission: avoid applying without genuine interest in energy and sustainability.
  • Overlooking async processing: failing to mention Celery or similar tools can hurt your chances.
  • Being too generic: don't submit a generic application; tailor every section to Octopus's specific needs.

📅 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 !