Application Guide

How to Apply for Senior Software Developer

at ONYX Insight

🏢 About ONYX Insight

ONYX Insight is a cleantech leader using predictive analytics to optimize wind energy performance globally, reducing downtime and boosting production. Their mission-driven focus on renewable energy and innovative use of data make them a standout employer for those passionate about sustainability and cutting-edge technology.

About This Role

As a Senior Software Developer on contract, you'll architect and build robust C# .NET services for high-volume sensor data ingestion and processing within a modular monolith. Your work directly impacts wind turbine efficiency and reliability, enabling real-time analytics that drive operational decisions across global wind farms.

💡 A Day in the Life

Your day starts with a stand-up to sync on pipeline throughput and any issues. You then dive into designing a new service boundary for sensor data ingestion, writing clean C# code with unit tests, and reviewing a PR for a PostgreSQL migration. After lunch, you pair with a frontend engineer to refine API contracts, then spend the late afternoon monitoring pipeline performance and tweaking async message flows for efficiency.

🚀 Application Tools

Generate Cover Letter

AI-powered, tailored for ONYX Insight

Interview Prep

Practice questions for this role

🎯 Who ONYX Insight Is Looking For

  • Deeply experienced in C# .NET (5+ years) with a strong grasp of clean architecture, SOLID principles, and modular monolith design patterns.
  • Proven track record building distributed systems with async messaging (e.g., RabbitMQ, Azure Service Bus) and event-driven architectures for high-throughput data pipelines.
  • Expert in PostgreSQL schema design, migrations, and writing efficient queries for large datasets, with experience in data ingestion pipelines handling high-volume sensor data.
  • Collaborative and API-focused, able to define clean contracts for frontend engineers and contribute to CI/CD pipelines for reliable deployments.

📝 Tips for Applying to ONYX Insight

1

Highlight specific experience with modular monoliths and clean architecture in your resume—mention any projects where you refactored a monolith into modular services.

2

Quantify your impact on data pipelines: e.g., 'Designed a pipeline processing 10M sensor readings/day with 99.9% uptime.'

3

Emphasize your async messaging expertise by naming the technologies (e.g., RabbitMQ, Kafka) and describing patterns like competing consumers or event sourcing.

4

Tailor your cover letter to mention wind energy or IoT data—show you understand the domain's challenges like time-series data and real-time processing.

5

Prepare a concise code sample or design document that demonstrates clean architecture principles and testable C# code—attach it if possible.

✉️ What to Emphasize in Your Cover Letter

['Your deep C# .NET expertise with clean architecture and SOLID principles, citing specific projects where you applied these.', "Experience with high-volume data ingestion and PostgreSQL performance tuning, linking to the company's sensor data needs.", 'Proficiency in async messaging and event-driven systems, showing you can design scalable worker processes.', 'Passion for renewable energy and how your skills can help ONYX Insight optimize wind turbine performance globally.']

Generate Cover Letter →

🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Review ONYX Insight's blog or case studies on predictive analytics for wind turbines to understand their data sources and algorithms.
  • → Familiarize yourself with their product offerings like 'Blade Insights' or 'Fleet Analytics' to grasp the domain context.
  • → Look into their tech stack beyond C#—they might use Azure, Docker, or specific IoT protocols—tailor your discussion.
  • → Check recent news about their partnerships or deployments to show awareness of their market impact.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Design a data ingestion pipeline for high-frequency sensor data (e.g., 10,000 readings/sec) using C# services and message queues.
2 How would you structure a modular monolith to allow future extraction into microservices? Discuss boundaries and communication patterns.
3 Write a PostgreSQL query to aggregate time-series sensor data efficiently, and discuss indexing strategies.
4 Explain your approach to testing async workflows and worker processes in .NET (e.g., using test harnesses or in-memory buses).
5 Describe a time you dealt with a production issue in a distributed system—how did you debug and fix it?
Practice Interview Questions →

⚠️ Common Mistakes to Avoid

  • Don't focus solely on microservices experience—they use a modular monolith, so emphasize monolith design skills.
  • Avoid generic descriptions of 'full stack' work; this role is backend-heavy with data pipelines and API contracts.
  • Don't neglect testing and CI/CD—mention how you ensure robustness through automated tests and deployment pipelines.

📅 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 ONYX Insight!

← Back to Job Listing Apply Now →