Application Guide

How to Apply for Senior Backend Engineer - Ruby on Rails (m/f/d)

at Global Changer

🏢 About Global Changer

Global Changer is at the forefront of climate tech, providing an efficient platform that helps B2B companies achieve Net-Zero emissions through automated data solutions. Its mission-driven team combines technical excellence with environmental impact, making it a unique place to work where your code directly contributes to sustainability.

About This Role

As a Senior Backend Engineer, you will own end-to-end backend services in the Rails codebase, focusing on the Corporate Carbon Footprint (CCF) module. You'll drive architectural decisions for data-heavy workflows, ensuring scalability and performance while translating complex domain requirements into robust technical solutions.

💡 A Day in the Life

Your day might start with a standup discussing the CCF module's data pipeline, followed by designing a new API endpoint for carbon data ingestion. After lunch, you'll dive into optimizing a slow Postgres query, then review a colleague's pull request focusing on code quality. The day ends with a brainstorming session on architectural improvements to handle increasing data volumes.

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🎯 Who Global Changer Is Looking For

  • Has 7+ years of backend experience with deep Ruby on Rails expertise, including designing and scaling Postgres databases with complex queries, indexing, and live migrations.
  • Proven track record of architecting data-heavy systems, particularly in environments requiring high performance and scalability (e.g., carbon footprint calculations).
  • Leads by example in code quality, with experience conducting thorough code reviews, refactoring legacy code, and making principled trade-offs around technical debt.
  • Fluent in English, based in EU (CET ±1), and holds a valid work permit for the region.

📝 Tips for Applying to Global Changer

1

Highlight specific examples of scaling Postgres at scale, such as optimizing slow queries or migrating large datasets without downtime.

2

Emphasize experience with data-heavy workflows, ideally related to environmental data, carbon calculations, or similar domains.

3

Showcase leadership in code quality: mention specific refactoring projects or code review practices you've implemented.

4

Tailor your CV to demonstrate ownership of backend services end-to-end, including API design and background processing.

5

In your cover letter, connect your technical skills to the mission of reducing carbon emissions—show genuine interest in climate tech.

✉️ What to Emphasize in Your Cover Letter

['Your deep Rails and Postgres expertise, with concrete examples of handling data at scale.', 'Your experience driving architectural decisions and setting technical direction for a codebase.', "Your passion for sustainability and how your work aligns with Global Changer's mission.", 'Your ability to work autonomously in a remote EU team and communicate effectively in English.']

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🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Understand the basics of Corporate Carbon Footprint (CCF) and its three scopes (Scope 1, 2, 3).
  • → Explore Global Changer's platform and read any case studies or blog posts about their technology stack.
  • → Look into the company's competitors in the carbon accounting space (e.g., Plan A, Greenly) to understand differentiation.
  • → Review recent news or funding rounds to gauge the company's growth stage and market position.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Design a data model for tracking corporate carbon footprints across multiple emission scopes.
2 How would you optimize a slow Postgres query that aggregates millions of rows for a carbon report?
3 Describe a time you had to refactor a legacy Rails monolith to improve performance—what trade-offs did you make?
4 How do you ensure data integrity and consistency during background job processing for carbon calculations?
5 Discuss your approach to technical debt: when do you prioritize paying it down vs. shipping new features?
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⚠️ Common Mistakes to Avoid

  • Don't submit a generic application—failing to mention Rails or Postgres expertise will make you look unprepared.
  • Avoid downplaying the importance of data performance; this role is heavily focused on scalability.
  • Don't ignore the remote EU requirement—applying without a valid work permit or outside CET ±1 will be rejected.

📅 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 Global Changer!

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