Senior .NET Developer

B3 Consulting's vision is to create a world of technology in which people come first. We come from Sweden, and our mission is to take care of how we live and work.

Our "Care" philosophy results in technology meeting care, which allows us to build long-term relationships while creating innovative solutions.

At B3, we unleash the potential of companies through IT outsourcing in a unique, Scandinavian model. We are one of the fastest growing companies in Poland, awarded the title of "Business Gazelle" in 2023 💪

If, like us, you value:

💥 Energy

💡 Logic

💻 Experience

This is great - we fit together perfectly!

The project comes from Natue/Forestry industry and concerns building a large-scale, real-time platform powering mobile apps, IoT devices, and backend services for hundreds of thousands of users — even under extreme peak loads. We’re looking for engineers passionate about building robust, long-lasting systems — not just shipping features.

Your tasks:

· Design, build, and operate backend microservices using .NET (C#, ASP.NET Core)

· Build and evolve client-facing APIs with strong focus on: versioning; backward compatibility; long-term maintainability

· Work with event-driven systems (Google Pub/Sub, Kafka)

· Improve platform stability, performance, and scalability

· Participate in production support and incident resolution

· Collaborate closely with platform, product, embedded, and mobile teams

· Take end-to-end ownership from design to production

Your skills:

·Strong experience with .NET backend development (C#, ASP.NET Core)

· Solid understanding of microservice architectures

· Experience building production-grade APIs

· Experience with messaging systems (Google Pub/Sub and/or Kafka)

· Proven experience running and maintaining production systems

· Strong testing and debugging skills (unit, integration, performance)

· Comfortable with Git and modern development workflows (code reviews, CI/CD)

· Clear communication and documentation skills

· Strong ownership mindset — you care about what happens after deployment

· Willingness to use AI tools responsibly to improve development productivity

· Fluent in English communication

On board with B3 you will receive:

• Health and sports benefits tailored to your needs

• Free running and swimming training, internal triathlon team, joint competitions (Warsaw)

• Tailor-made development activities to deepen expert knowledge

• Cyclical initiatives allowing development in IT fields other than the current one

We are waiting for you! 🦓