Senior Full Stack (.NET) Developer

Job Description

We are looking for a highly skilled Senior Full Stack Developer to join our team and contribute to building modern, scalable web applications. This is a long-term engagement with 100% remote work, offered on a B2B contract.

Rate: 160–180 PLN/h (B2B)
Location: Remote (100%)
Languages required: Polish – very good; English – B2/C1

What We’re Looking For

• 4+ years of professional software development experience (ideally 6+ years).
• Strong expertise in .NET Core / .NET 6+, ASP.NET Core, C#, and Web API.
• Experience developing RESTful APIs and integrations, working with SQL databases.
• Proficiency in frontend frameworks (Angular 2+, React, or Vue.js) and HTML5.
• Familiarity with unit & integration testing, clean coding practices, and Git.
• Ability to work across the stack (frontend, middleware, backend) with attention to performance and code quality.
• Comfortable using GenAI tools (e.g., Cursor, GitHub Copilot).
• Strong understanding of OOP, design principles, and patterns.
• Excellent collaboration skills with remote, distributed teams, strong ownership, and self-management.
• Good communication in Polish (very good) and English (B2/C1).

Nice-to-Have (Desired Skills)

• Experience with TDD, automated tests, Agile methodologies, pair/mob programming (XP).
• Database experience with Microsoft SQL Server, PostgreSQL, Entity Framework Core, ADO.NET.
• Frontend experience with Bootstrap, TypeScript, JavaScript, CSS3.
• Knowledge of data sources (Data Warehouses, Lakehouses).
• Experience with Power BI REST APIs.
• Hands-on experience with AI engineering, including:
• Agent frameworks/orchestration (planning, multi-agent routing, tool calling).
• Retrieval-augmented generation (RAG), embeddings, vector/hybrid search (Azure AI Search).
• Microsoft Semantic Kernel or similar .NET agent orchestration tools.
• Long-running workflows and human-in-the-loop scenarios.
• Ability to identify and proactively avoid performance issues.

Day-to-Day Responsibilities

• Hands-on development across frontend, backend, and APIs, ensuring clean and maintainable code.
• Participate in daily scrums and collaborate actively with the team.
• Deliver features based on planning, grooming, mockups, and user stories.
• Design and build scalable applications using .NET (C#/ASP.NET Core), modular monoliths, and microservices.
• Implement and optimize RAG pipelines (document ingestion, embeddings, retrieval).
• Build and expose APIs (REST/GraphQL) for internal/external integrations.
• Contribute to CI/CD pipelines, code reviews, and testing.
• Collaborate in pair/mob programming sessions when needed.
• Work closely with support teams on deployments and resolving critical issues.