Application Guide

How to Apply for Senior Software Engineer - Mobile (m/f/d)

at 1KOMMA5°

🏢 About 1KOMMA5°

1KOMMA5° is a fast-growing climate tech company on a mission to make buildings CO2-neutral through integrated clean energy, mobility, and heat solutions. Their holistic approach and focus on real-world impact make them a unique place to work for engineers who want to fight climate change with technology.

About This Role

As Senior Software Engineer - Mobile, you'll own the technical direction of the Installation Manager mobile app, which directly helps field teams install clean energy systems more efficiently. You'll ship reliable features, drive automated testing and continuous release, and mentor fellow engineers—all while working closely with product and design to turn field feedback into a better product.

💡 A Day in the Life

You start your day by checking async updates from the team (Slack, GitHub, Linear) and reviewing PRs. You might pair with a backend engineer on an API contract, then write tests for a new feature. In the afternoon, you mentor a junior engineer on testing strategies, and later join a product sync to discuss field feedback and prioritize the next sprint.

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Interview Prep

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🎯 Who 1KOMMA5° Is Looking For

  • Has shipped and maintained at least one mobile app used in production (any stack, Flutter not required) and can talk about architecture decisions and trade-offs.
  • Has a genuine testing mindset: they've built or driven automated testing and continuous delivery pipelines, not just used them.
  • Communicates openly and proactively in a remote, async environment, and thrives without daily synchronous check-ins.
  • Lifts the people around them through mentoring, code review, and knowledge sharing, and cares deeply about code quality and long-term maintainability.

📝 Tips for Applying to 1KOMMA5°

1

In your resume and cover letter, explicitly mention your experience with automated testing and continuous delivery for mobile apps—give specific examples (e.g., 'built CI pipeline with X that ran Y tests on every PR').

2

Highlight any work you've done that directly impacted field teams or operational efficiency, as the app is used by installers in the field.

3

Since the role is remote and async, demonstrate your communication skills: mention how you've collaborated across time zones or used tools like Slack, Notion, or Jira asynchronously.

4

If you have experience with Flutter, mention it, but don't worry if you don't—the JD explicitly says it's not required. Focus on your mobile engineering fundamentals.

5

Show that you care about the company's mission: mention sustainability, clean energy, or climate tech in your cover letter or interview answers.

✉️ What to Emphasize in Your Cover Letter

['Your experience building and maintaining production mobile apps, with emphasis on architecture, performance, and long-term maintainability.', "Your testing mindset: specific examples of how you've implemented automated testing and continuous delivery for mobile.", "How you've mentored other engineers and contributed to team growth (e.g., leading code reviews, pair programming, or creating documentation).", "Your alignment with 1KOMMA5°'s mission: why you want to work on decarbonizing buildings and how your skills can help."]

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🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Read about 1KOMMA5°'s product ecosystem: their Installation Manager app, energy management system, and hardware integration (solar, heat pumps, EV chargers).
  • → Understand their business model: they offer holistic CO2-neutral building solutions, not just solar panels. How does the mobile app fit into that?
  • → Look at their blog or press releases to see recent milestones, partnerships, or funding news.
  • → Check their engineering culture: do they have a tech blog? Any talks or open source contributions? This gives insight into their values.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Walk me through a mobile app you shipped: what were the key architectural decisions and why?
2 How do you approach testing for mobile? Can you describe a time you improved test coverage or built a CI pipeline?
3 Tell me about a time you mentored a junior engineer or helped a teammate grow. What was your approach?
4 How do you handle feedback from field users? Describe a time you used real user feedback to change a feature.
5 This role is remote and async. How do you stay productive and communicate effectively without being in the same office?
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⚠️ Common Mistakes to Avoid

  • Don't apply without mentioning testing or CI/CD experience—it's a core requirement and not just a nice-to-have.
  • Avoid generic statements like 'I'm passionate about mobile development.' Instead, be specific about what you've built and how it made an impact.
  • Don't overlook the mentoring aspect: if you only focus on your individual contributions, you'll miss a key part of the role. Show you can grow others.

📅 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 1KOMMA5°!

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