Senior .NET Engineer: Data Platform & AI Agents

b3consultingpoland; Kraków; Hybrid; PLN 180,000 - 240,000; Full time

Job summary

B3 Consulting Poland is seeking a Senior .NET Engineer to design and build data platform services for a multi-tenant SaaS in Kraków. You will work with .NET, PostgreSQL and related tech to deliver scalable backend solutions.

You will collaborate with Data Platform, Analytics, Support and Product teams to refine requirements, ensure code quality for AI-generated tooling, and contribute to high-performance systems in a dynamic, international setting.

Qualifications

• Senior-level backend experience with .NET/C# in multi-tenant SaaS environments.
• Strong SQL/PostgreSQL design and query optimization.
• Performance/memory-aware design and .NET architecture knowledge.
• Experience with AI/agents and evaluating agent outputs.
• Testing/quality discipline: unit/integration tests; good documentation.
• Fluent English (C1).
• Eligibility to work in Poland.

Responsibilities

• Design data platform services in a multi-tenant SaaS using .NET, EF/Dapper and PostgreSQL.
• Build tools to generate performant queries tailored to customer data models, optimizing performance and cost.
• Develop agentic tooling and collaborate with Data Platform, Analytics, Support and Product teams to ensure AI-generated code quality.

Skills

Backend .NET/C#

SQL / PostgreSQL

Performance optimization

AI/agents

Testing & docs

English (C1)

Poland work eligibility

Job description

B3 Consulting Poland is seeking a Senior .NET Engineer to design and build data platform services for a multi-tenant SaaS in Kraków. You will work with .NET, PostgreSQL and related tech to deliver scalable backend solutions.

You will collaborate with Data Platform, Analytics, Support and Product teams to refine requirements, ensure code quality for AI-generated tooling, and contribute to high-performance systems in a dynamic, international setting.