Senior .NET Engineer (Data Platform & AI Agents)

What you work on today shapes where you’ll be tomorrow.

Looking for your next challenge as a Senior .NET Engineer (Data Platform & AI Agents)? We may have the right opportunity for you.

At B3, we start with people and their experience. We match projects to your skills and professional growth path. Our consultants work across a wide range of industries and technologies, delivering IT projects both in Poland and internationally. This allows you to build your career in a deliberate way - not by chance.

We are part of an international organization listed on Nasdaq Stockholm, operating in 11 countries. In Poland, we operate with full autonomy. We choose our technologies, processes, and ways of working while maintaining the highest professional standards.

Join us today.

• Designing and developing data platform services in a multi-tenant SaaS architecture (data ingestion, schema management, snapshots, calculated fields, exports) using .NET, Entity Framework/Dapper and PostgreSQL

• Building tools that dynamically generate performant queries, tailored to each customer's unique data model - with a focus on performance and cost optimization (bulk ingestion, streaming, complex SQL queries)

• Senior-level, 5+ year experience building production, performant and scalable backend services in .NET/C# (preferably in a multi-tenant SaaS environments)

• Strong SQL and PostgreSQL skills (schema design, query optimization)

• • Microsoft Fabric or Spark

  • MCP servers or exposing internal APIs as agent-callable tools

  • LLM evaluation (eval suites, behavioral test design, benchmarking agent workflows)