Senior .NET developer

Spyrosoft Ltd; Polska; Hybrid; PLN 180,000 - 300,000; Full time

Job summary

Spyrosoft Ltd. is seeking a Senior .NET Backend Developer to contribute to a mobile-first HR/payroll platform. You will build robust services and APIs, collaborate with an experienced engineering team, and deliver scalable software within an Agile framework.

The role emphasizes autonomy, ownership, and teamwork, with opportunities to work on integrations and modern engineering practices, including AI-assisted development tools.

Qualifications

• Very strong .NET experience in backend development.
• Solid knowledge of DDD, CQRS and clean architecture.
• Experience with REST APIs and API-first development across multiple systems.
• Strong SQL skills including data modeling and query optimization.
• Experience with cloud environments (Azure preferred).
• Experience working with distributed/microservices architectures.
• Good understanding of automated testing (unit, integration).
• Strong communication skills and ability to articulate technical ideas clearly.
• Very good English (spoken and written).
• Team-oriented mindset with autonomy in delivering features and tasks.
• Experience using GitHub Copilot or other AI-assisted development tools.

Responsibilities

• Design, develop, and maintain backend services and APIs in .NET.
• Collaborate with a cross-functional Agile team.
• Deliver robust, secure, scalable software aligned with requirements.
• Build and maintain integrations with internal and external systems.
• Troubleshoot and support codebases, including legacy components.
• Provide technical guidance and contribute to architecture discussions.
• Document decisions, progress, and architectural considerations.
• Prepare accurate estimates and own deliverables.
• Engage in development initiatives and continuous improvement.
• Stay up to date with modern engineering trends and AI-assisted tooling.

Skills

.NET backend development

DDD

CQRS

REST APIs

SQL

Azure

NHibernate/EF Core

AI tooling

Distributed microservices

Testing (unit/integration)

GitHub Copilot

Tools

RabbitMQ

Kafka

Azure Service Bus

Docker

Kubernetes

Job description

Tech Stack:

• .NET 8/10 and C#

• Domain-Driven Design (DDD)

• Microservices Architecture

• CQRS

• SQL

• Azure

• ORM NHibernate/EF core

• AI Tooling

Required Qualifications:

• Very strong .NET experience (modern backend development)

• Solid knowledge of DDD, CQRS and clean architecture principles

• Experience with REST APIs and API-first development Integration experience (multiple systems, protocols)

• Strong SQL skills, including query optimization and data modeling

• Experience with cloud environments (Azure preferred)

• Experience working with distributed/microservices architectures

• Good understanding of automated testing (unit, integration)

• Strong communication skills and ability to clearly articulate technical ideas

• Very good English (spoken and written)

• Team-oriented mindset combined with relative autonomy in delivering features and tasks

• Experience using GitHub Copilot or other AI-assisted development tools

Nice to Have:

• Experience with messaging systems (e.g., RabbitMQ, Kafka, Azure Service Bus)

• Experience with CI/CD pipelines and containerization (Docker, Kubernetes)

• Background in finance / accounting / ERP domains

Project Description:

We are seeking a Senior .NET Backend Developer to contribute to the development of our integrated, mobile-first HR and payroll platform. We aim to deliver high-quality, scalable solutions within an Agile framework. As a backend developer, you will work closely with an experienced engineering team, contributing to the design and delivery of robust services and APIs that power the platform. You will actively engage in development initiatives, collaborate with stakeholders, and support the team with clear communication and technical insight. The role requires a balance of autonomy, ownership, and strong teamwork.

Main responsibilities:

• Designing, developing and maintaining backend services and APIs in .NET

• Collaborating with a skilled cross-functional Agile team

• Delivering robust, secure, and scalable software aligned with business and technical requirements

• Building and maintaining integrations with internal and external systems

• Troubleshooting and supporting codebases, including components created by other engineers

• Providing technical guidance and contributing to solution design and architecture discussions

• Documenting decisions, progress, and architectural considerations in line with project processes

• Preparing accurate estimates and taking ownership of assigned deliverables

• Actively engaging in development initiatives and contributing to continuous improvement

• Staying up to date with modern engineering trends and emerging technologies

• Using AI tools effectively to enhance productivity and code quality