Senior Software Engineer - Backend, OE Engineering
Tokyo
Kraken ➡ OE Engineering 🐙 🛠️ – All Roles /
Full-time /
Hybrid
Help us use technology to make a big green dent in the universe!
Kraken powers some of the most innovative global developments in energy.
We’re a technology company focused on creating a smart, sustainable energy system. From optimising renewable generation, creating a more intelligent grid and enabling utilities to provide excellent customer experiences, our operating system for energy is transforming the industry around the world in a way that benefits everyone.
It’s a really exciting time in energy. Help us make a real impact on shaping a better, more sustainable future.
About the Team
We're on a mission to create intuitive, engaging, and scalable digital experiences for consumers - from customer signup journeys to campaign integrations and beyond, our projects are as diverse as our ideas, and we always keep users front and center.
Some of the things you might work on:
・Building dynamic dashboards that transform with each campaign theme
・Integrating LINE accounts so customers can sign up for campaigns with a single tap
・Blending promotional content seamlessly into core product functionality
・Surfacing real-time campaign performance through slick, interactive charts
We're not just building features - we're crafting flexible, maintainable, and scalable solutions that make life easier for both our partners and our internal teams.
Our team’s still growing, which means you’ll be part of shaping how we work. We move fast, learn quickly, and care deeply about clean code, smart testing, and good monitoring. We believe great communication is key: we lean on quick face-to-face chats or huddles for fast-moving topics, and use Slack, Asana, and other async tools to keep things running smoothly in the background.
We’re transparent, collaborative, and not afraid of a bit of trial-and-error. Expect regular reviews, lots of learning, and plenty of chances to make your mark.
About the Role
We're looking for a talented software engineer to help solve exciting challenges for our sustainability-focused energy retailer client.
Our team members are passionate about technology and making a positive impact on the planet. They're self-motivated problem-solvers who love taking initiative and helping others grow while delivering great results for customers and teammates.
We value people who are adaptable, collaborative, and thoughtful decision-makers. They embrace change, create an inclusive environment where everyone belongs, and stay calm under pressure while always being ready to help.
What you'll do
- Design, build, and maintain high-performing, reliable code to meet the unique business needs.
- Improve code quality with daily basis small refactoring with better naming, better coupling, better tests.
- Collaborate with stakeholders via Product Manager to automate and improve real-world processes.
- Strive to find simple, elegant solutions—even for complex, region-specific requirements.
- Actively contribute to the codebase with a hands-on, problem-solving mindset.
- Support fellow engineers by pairing, giving thoughtful design and code reviews, and sharing knowledge to help everyone grow.
- Quickly investigate and resolve technical issues, including working with other teams when our operations or users are impacted.
- Follow a culture of frequent feedback, team retros, and regularly reviewing tools and workflows to keep improving how we work.
- Prioritize delighting both our customers and internal colleagues by designing intuitive, user-friendly experiences.
- Use monitoring tools (Sentry or Datadog) and identify the issues or discover opportunities to make our application more reliable.
- Place an emphasis on transparency, taking ownership and iterating on processes if something isn’t working—always aiming to deliver quality and value.
What you'll have
- We’re not obsessed with checking boxes. We value curiosity, empathy, and a love for building. But here’s what helps:
- Python - experience with at least one web framework (Django, Flask, etc.)
- Domain modelling
- HTTP and REST APIs
- Writing robust and error-resistant code
- Celery and async processing
- Postgres
- Thoughtful problem-solving with attention to detail
- Strong communication and team collaboration skills
- Familiarity with Git and version control workflows
- Experience with front-end applications (React, TypeScript, etc.).
- Experience with GraphQL.
- Experience with AWS infrastructure.
- Experience with Infrastructure as Code (Terraform, etc.)
- Japanese language ability is a bonus, but not required. We’re a global, inclusive team.
- Backend: Python, Django, Celery, Graphene, Postgres, Terraform, AWS
- Frontend: TypeScript, React, Next.js, GraphQL, Storybook, XState, Storyblok, Typeform
- Tooling & Testing: CircleCI, Sentry, Datadog, pytest
Nice-to-haves:
Our Tech Stack:
Our Culture
- We are at the forefront of innovation in the energy industry - and our success is driven by our people.
- Loves learning and enjoys sharing knowledge.
- Cares deeply about users and the impact of your work.
- Engages with people from diverse and multicultural backgrounds with sensitivity, empathy, and warmth.
- Gives and receives constructive feedback with openness, learns from challenges, and grows with a strong sense of purpose.
- Can thrive in a fast-moving, collaborative environment.
- Believes technology can and should fight climate change.
- Is excited to shape a modern engineering culture.
- Whether you're a seasoned engineer or just starting your software engineering journey, if you’re passionate and kind, we want to hear from you.
To thrive at Kraken, you'll be someone who:
Why join us?
- Our company culture - we won best company to work for in 2019 and our CEO, Greg has recorded a podcast about our culture and how we empower our people.
- Flexible working environment - genuine work life balance here, we are in the top 5 companies in the UK, we treat you as a human, and do our best to make work and life merge smoothly together.
- Relaxation - we don’t count your holidays here, we work hard, and so we know you need to play hard as well (within reason of course).
- Equity Options Scheme - you own your own part of the business, share options in the whole Octopus Energy Group so we all work together towards success.
- Office culture - have a certain tech requirement? We’ll do our best to get it. Our offices are also stocked with fruit, breakfast, great coffee and soft drinks. Weekly on a Friday we all get together (this happens virtually too) for company updates and drinks - we call it Family Dinner.
- Your development is important - we support and help with development including internal and external courses, learning, study support etc, all bespoke to 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. Across Kraken, we're looking for genuinely decent people who are honest and empathetic. Our people are our strongest asset and the unique skills and perspectives people bring to the team are the driving force of our success. 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.
