Expert .NET Engineer

Salary range: B2B 44-47 E/h + VAT 💰

Ciklum is looking for an Expert .NET Engineer to join our team full-time in Poland.

We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts and product owners, we engineer technology that redefines industries and shapes the way people live.

About the role:

As a Expert .NET Engineer, become a part of a cross-functional development team engineering experiences of tomorrow. The project focuses on maintaining and extending mission-critical trading systems ensuring stability, scalability, and real-time data processing. You will work in a cross-functional agile team, addressing performance challenges, modernizing services, and integrating new modules that handle high-volume trading communication.

This role requires strong technical expertise with modern .NET 8, microservices, and containerized deployments, as well as experience maintaining high-availability systems used in financial markets.

Responsibilities:

• Design, implement, and maintain backend components using C# / ASP.NET 8.0

• Develop and manage hosted services and background workers for real-time trading workflows

• Apply dependency injection (DI) and other SOLID principles for maintainable architecture

• Build and document RESTful APIs with Swagger / OpenAPI

• Integrate data access layers using Entity Framework Core and MSSQL Server

• Implement and maintain TCP/IP socket-based communication between trading modules

• Write and maintain unit/integration tests using XUnit to ensure code quality

• Containerize services using Docker / Docker Compose and maintain deployment pipelines via GitLab CI/CD

• Collaborate with QA, DevOps, and product teams through Jira for sprint planning, issue tracking, and releases

• Contribute to documentation using AsciiDoc standards

• Manage NuGet dependencies and contribute to shared internal packages

• Support system troubleshooting and performance optimization for production workloads

Requirements:

• Strong experience in C#, ASP.NET Core (up to .NET 8)

• Proven knowledge of hosted/background services and dependency injection

• Hands-on experience designing and consuming REST APIs

• Proficiency in Swagger/OpenAPI, Entity Framework, and MSSQL Server

• Solid understanding of TCP/IP socket communication

• Practical experience writing tests with XUnit

• Experience using GitLab for version control and CI/CD

• Working knowledge of Docker and Docker Compose for local development and deployment

• Familiarity with Jira and AsciiDoc for agile collaboration and documentation

• Experience publishing and consuming internal libraries using NuGet

Desirable:

• Experience with Redis Cache for performance optimization

• Familiarity with Solace PubSub+ Message Broker or other event-driven messaging systems (Kafka, RabbitMQ, etc.)

• Experience with high-availability and fault-tolerant architectures in financial or trading systems

• Knowledge of monitoring and performance tools for .NET microservices

What`s in it for you?

• Strong community: Work alongside top professionals in a friendly, open-door environment

• Growth focus: Take on large-scale projects with a global impact and expand your expertise

• Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications

• Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies

• Flexibility: Enjoy flexibility – full remote working possibilities

• Care: We’ve got you covered with company-paid medical insurance, mental health support, and financial & legal consultations

About us:

At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress.With delivery centers in Wrocław and Gdańsk, our 300+ professionals in Poland drive forward-thinking solutions for global clients. Join a community where collaboration sparks innovation—and your impact reaches millions.Want to learn more about us? Follow us on Instagram, Facebook, LinkedIn.

Explore, empower, engineer with Ciklum!

Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum.