Senior .NET WPF Developer (f/m/x)

🏢 Summary: Permanent .NET Developer role focused on building and maintaining desktop and business-critical applications in a mixed .NET and Java environment. The position covers development, integrations, troubleshooting, code reviews, documentation, and CI/CD support within international Agile teams. The offer includes hybrid work, flexible hours, private healthcare, insurance, training, and conference access. 🗂️ Requirements: Commercial .NET development experience, Proficiency in C#, Experience with Java-based applications or Java development, Desktop application development experience, Backend development and API-building experience, Knowledge of relational databases, Working knowledge of Git, Experience working in Agile/Scrum environments, English proficiency at B2 level or higher 📃 Skills: .NET, C#, Java, WPF, WinForms, REST, Git, SQL, CI/CD, Agile, Scrum 🏢 Description: For our client we are looking for a candidate for the position of .NET developer . In this role, you will be responsible for developing and maintaining desktop applications as well as business-critical systems in a mixed technology environment based on .NET and Java. Key responsibilities: Design, develop, and maintain desktop applications using .NET technologies Build and support business applications and system integrations within a .NET and Java ecosystem Analyze business and technical requirements, implementing new features and improvements Enhance and maintain existing applications and systems Identify, troubleshoot, and resolve technical issues Collaborate closely with distributed international teams Participate in code reviews to ensure code quality and best practices Prepare and maintain technical documentation Support deployment processes as well as CI/CD pipelines Requirements: Experience in .NET development Solid knowledge of C# Experience working with Java-based applications or Java development Hands-on experience in desktop application development (e.g., WPF, WinForms, or similar) Experience with backend development and building APIs Familiarity with relational databases Working knowledge of Git Experience in Agile/Scrum environments English proficiency at B2 level or higher Tech Stack: .NET Framework, .NET Core, .NET 5+, C#, Java, REST APIs, Git, MS SQL Server, SQLite, PostgreSQL, CI/CD Nice to have: Experience with WCF Knowledge of DevExpress Experience in enterprise environments or legacy system modernization Offer: Permanent employment contract Private medical care Group insurance Sports card Flexible working hours Hybrid work model (50% remote/ 50% office) Certified training programs and continuous professional development Access to e‑learning platforms Opportunities to attend IT conferences, including international events Language classes and online language learning tools

🏢 Summary: Senior .NET Developer role focused on transforming a data-intensive analytical platform for the cloud. The position involves scalable architecture design, legacy modernization, SOA-based development, user support, and close collaboration with engineering, analysis, and QA teams. 🗂️ Requirements: 5+ years of .NET software development experience, Web services design and implementation expertise, AWS and cloud environment experience, Redux and Context API mastery in React applications, Software design principles and best practices, Advanced English 📃 Skills: .NET, AWS, React, Redux, Context, SOA, Webservices 🏢 Description: We are looking for a Senior .NET Developer to join our team and contribute to the cloud transformation of a data-intensive analytical platform. In this role, you will collaborate with innovative and diverse professionals from around the world, designing scalable architectures and modernizing legacy components to ensure performance and reliability. Your tasks Contributing to the cloud transformation of a data-intensive analytical platform by designing scalable architectures and modernizing legacy components Ensuring continuous technological evolution of the product by proposing and implementing modern frameworks and architectural improvements Applying Service Oriented Architecture (SOA) concepts in software design and development Providing timely and courteous support to platform users, ensuring issues are understood, analyzed, and resolved promptly Collaborating closely with a team of software engineers, analysts, and quality engineers to design and build software solutions that meet business needs Adhering to team design and coding procedures and standards Requirements Minimum 5 years of experience in software development with a strong focus on .NET technologies Deep expertise in designing and implementing web services Practical experience with AWS and cloud environments Hands-on mastery of Redux and Context API in React applications Strong understanding of software design principles and best practices Advanced level of English Nice-to-have requirements Experience with C#

🏢 Summary: Remote, long-term B2B contract for an experienced .NET Software Developer supporting a European Union organization. The role covers enterprise-system design and development, technical leadership, solution architecture, quality optimization, releases, testing, and 2nd/3rd-line support. Rate: 215 PLN net + VAT per hour. 🗂️ Requirements: Completed at least one full solution lifecycle, Expertise in enterprise-level software development, UML application design, Data, business-logic and UI-layer design and development, Scrum experience, Technical team leadership capability, Technical-solution documentation skills, Problem-solving skills, At least 2 years of experience with mission-critical complex enterprise systems, Experience with asset and/or human-resources management and financial-management systems, At least one internationally recognized intermediate software-development certification relevant to the domain 📃 Skills: .NET, UML, Scrum, Enterprise, Testing, Prototyping, Configuration, Deployment 🏢 Description: Currently, for one of our Partners, we are looking for an experienced Software Developer .NET (m/f/n) to support a long‑term project delivered for an organization of the European Union based in Warsaw. Requirements: Has gone at least 1 time through the complete lifecycle of the solution Expert in developing enterprise level software systems in specified technology domain Knows UML and can design applications in UML Proficient in designing and developing: data layer, business logic layer and UI layer Worked in Scrum developments Is capable for leading technical teams Holds ability to document effectively technical solutions Presents problem solving skills Specific requirements At least 2 years of experience with mission critical complex enterprise systems including asset and/or human resources management, as well as financial management. At least 1 certification among: Intermediate level certificate in software development relevant to the domain or an equivalent certification recognized internationally (subject to acceptance as a valid credential by the Contracting Authority) Typical tasks and responsibilities Designs and develops the system Lead development teams Translates requirements into design Optimizes software from performance, security and quality points of view Produces technical documentation Estimates effort and time for development Sets software development standards Propose technical solutions for business needs and technical problems Collects and interprets software metrics Manages configuration and releases Contributes to requirements analysis, testing, quality assurance, change management, deployment Tests solutions and develops testing tools Documents developments Prototypes solutions Acts as 2nd and 3rd line support Offer: Rate: 215 PLN net +VAT/H Set-up: Remote B2B

🏢 Summary: 6-miesięczny kontrakt z możliwością przedłużenia dla Senior .NET Developera odpowiedzialnego za projektowanie, rozwój i utrzymanie skalowalnych aplikacji backendowych oraz API. Rola obejmuje współpracę z zespołami projektowymi, projektowanie architektury, optymalizację rozwiązań, utrzymanie systemów produkcyjnych i wsparcie mniej doświadczonych osób. 🗂️ Requirements: Minimum 6 lat komercyjnego doświadczenia w C#/.NET, Bardzo dobra znajomość .NET Core / .NET 6+, Doświadczenie w projektowaniu i rozwoju aplikacji backendowych oraz REST API, Znajomość wzorców projektowych i zasad SOLID, Doświadczenie w pracy z bazami danych SQL, Znajomość Git i praktyk CI/CD, Doświadczenie w Agile, Scrum lub Kanban, Bardzo dobra znajomość języka angielskiego 📃 Skills: C#, .NET, SQL, REST, Git, CI/CD, Agile, Scrum, Kanban, SOLID 🏢 Description: Poszukujemy doświadczonego Senior .NET Developera (C#) do realizacji projektu dla naszego klienta. Jest to kontrakt na 6 miesięcy z możliwością przedłużenia współpracy. Zakres obowiązków Projektowanie, rozwój i utrzymanie aplikacji backendowych w technologii C#/.NET. Tworzenie oraz rozwijanie wydajnych i skalowalnych usług oraz API. Współpraca z zespołem projektowym przy analizie wymagań biznesowych i technicznych. Dbanie o wysoką jakość kodu poprzez stosowanie dobrych praktyk programistycznych oraz udział w code review. Identyfikowanie i rozwiązywanie problemów technicznych oraz optymalizacja istniejących rozwiązań. Tworzenie i aktualizacja dokumentacji technicznej. Udział w projektowaniu architektury aplikacji oraz proponowanie usprawnień technologicznych. Współpraca z zespołami QA, DevOps oraz analitykami w celu sprawnej realizacji projektu. Wsparcie mniej doświadczonych członków zespołu oraz dzielenie się wiedzą. Aktywny udział w procesie wdrażania nowych funkcjonalności i utrzymania systemów produkcyjnych. Wymagania: Minimum 6 lat doświadczenia komercyjnego w programowaniu w C#/.NET . Bardzo dobra znajomość platformy .NET (.NET Core / .NET 6+). Doświadczenie w projektowaniu i rozwoju aplikacji backendowych oraz REST API. Znajomość wzorców projektowych i zasad SOLID. Doświadczenie w pracy z bazami danych SQL. Znajomość Git oraz praktyk CI/CD. Umiejętność pracy w metodykach Agile (Scrum/Kanban). Bardzo dobra znajomość języka angielskiego umożliwiająca pracę w międzynarodowym środowisku.

🏢 Summary: Remote B2B opportunity for a .NET Software Developer to design, build, and optimize mission-critical enterprise systems for a major European institution. The role includes end-to-end development, technical leadership, solution design, testing, release management, and advanced technical support, with occasional visits to Warsaw. 🗂️ Requirements: 4+ years of IT-relevant professional experience, 2+ years of relevant project or similar-role experience, 2+ years working with mission-critical complex enterprise systems, Experience with asset or human-resources management and financial-management systems, Expertise in enterprise-level .NET software development, Data, business-logic, and UI layer design and development experience, UML application design experience, Completion of at least one full software-solution lifecycle, Scrum development experience, Technical team leadership experience, Fluent English at B2 level or higher, Bachelor’s degree or equivalent 3 years of higher education in an ICT-relevant field, Intermediate .NET software-development certification or an accepted equivalent international certification 📃 Skills: .NET, UML, Scrum, ICT 🏢 Description: Software Developer (.NET) — own system design, lead technical teams, and drive end-to-end development. Far-site remote, 200 PLN net/h B2B. IT · Multiple locations · Fully Remote About the Client and our Role At Optiveum, we connect top IT professionals with exciting tech initiatives. In this case, we are the recruitment partner acting within the TimeDev Framework Agreement to provide outsourcing consultants for our partner organization . By taking part in this long-term project, you will be contributing as a Software Developer to support a major European institution. The Role We are looking for a Software Developer (.NET) to take an active role in designing, building, and optimizing enterprise-level software systems. In this position, you will lead development initiatives, implement robust solutions across data, business logic, and UI layers, and ensure software meets stringent security, performance, and quality standards. You will work closely with other technical teams to prototype solutions and support complex enterprise frameworks. Responsibilities Design and develop the system, translating requirements into technical design. Lead development teams and set software development standards. Design applications using UML and optimize software for performance, security, and quality. Propose technical solutions for business needs and solve complex technical problems. Estimate effort and time for development. Produce technical documentation and effectively document developments. Manage configuration, releases, and collect/interpret software metrics. Contribute to requirements analysis, testing, quality assurance, change management, and deployment. Test solutions, develop testing tools, and prototype new features. Act as 2nd and 3rd line technical support. Expectations Experience: Minimum 4 years of overall IT-relevant professional experience, including at least 2 years of project experience relevant to the profile (or in a similar position). Specific Domain Expertise: At least 2 years of experience with mission-critical complex enterprise systems, specifically including asset and/or human resources management, as well as financial management. Technology Stack: Expert in developing enterprise-level software systems in the .NET technology domain . Technical Skills: Proficient in designing and developing the data layer, business logic layer, and UI layer. Strong knowledge of UML and ability to design applications in UML. Completion of at least 1 full lifecycle of a software solution. Process & Leadership: Experience working in Scrum developments, capable of leading technical teams, and strong problem-solving skills. Language: Fluent English (minimum B2 level / CEFR). Education (Level 6): Minimum Bachelor’s degree (or 3 years of higher education confirmed by a diploma). An ICT-relevant degree is mandatory. Certifications Requirements You must possess at least one of the following: An Intermediate level certificate in software development relevant to the domain (.NET). An equivalent internationally recognized certification (subject to acceptance as a valid credential by the Contracting Authority). What We Offer Salary: max 200 net / hour. Contract Type: B2B agreement. Type of Work: Remote with occassional visits to the client HQ in Warsaw, Poland

🏢 Summary: Senior .NET Developer role focused on building and maintaining scalable back-end services for an electronic-component selection system and manufacturer database integrations. The position involves Azure and CosmosDB development, test automation, AI-assisted engineering, and close Agile collaboration with a US-based team. 🗂️ Requirements: 8+ years of .NET development experience, Senior-level problem-solving capabilities, C# experience, Azure cloud experience, CosmosDB experience, Practical use of AI development tools, Fluent English, Availability for daily meetings between 17:00 and 19:00 CET, Residence in Poland or eligibility to work in Poland 📃 Skills: .NET, C#, Azure, CosmosDB, Playwright, Selenium, GitHub, Copilot, ChatGPT, Cursor, Agile 🏢 Description: Your responsibilities - Design, develop, and maintain high-performance back-end services using .NET and C# for an established, scalable system used for selecting electronic components and integrating with manufacturer databases. - Work extensively with Azure cloud services and CosmosDB to build, maintain, and monitor resilient solutions. - Set up test automation structures and frameworks from scratch using tools such as Playwright or Selenium. - Actively use AI coding assistants, including GitHub Copilot, ChatGPT, or Cursor, to enhance productivity and troubleshooting; proactively share AI-assisted development practices with the team. - Collaborate directly with the US-based team in an Agile environment, participating in code reviews, sprint planning, and architectural discussions. - Communicate with business stakeholders to understand requirements and translate them into effective technical solutions. Requirements - Minimum 8 years of professional experience in .NET development, demonstrating a senior-level mindset and problem-solving capabilities. - Experience with C#, the Azure cloud ecosystem, and CosmosDB. - Practical experience using modern AI tools in daily software development and willingness to promote these practices. - Fluency in English to ensure seamless communication with US managers and developers. - Flexibility to align with US working hours, including daily meetings between 17:00 and 19:00 CET. - Residence in Poland and/or eligibility to work in Poland. Nice to have - Background or interest in Electrical Engineering. - General understanding of testing practices, CI/CD pipelines, and Git version control. - Knowledge of TypeScript or JavaScript. What we offer - 100% remote work. - Work in a Scandinavian culture built on logic and dialogue. - Health and sports benefits tailored to your needs. - Speed Coaching: short sessions that provide new perspectives and solutions. - Sports training, an internal team, and opportunities to take part in competitions. - Team events and development-focused meetups.

🏢 Summary: Senior .NET Developer role on a long-term, fully remote B2B project for an insurance and reinsurance client. The position focuses on developing and modernizing business-critical applications for migration to Microsoft Azure, using .NET, Blazor, SQL Server, Azure Functions, and Azure DevOps. 🗂️ Requirements: 5+ years of commercial .NET development experience, Commercial C# and .NET experience, Commercial Blazor experience or strong Full Stack experience with willingness to learn Blazor, SQL Server experience, Microsoft Azure experience, Azure Functions experience, Azure DevOps experience, English proficiency at B2 level or higher, Independent, proactive work in an Agile environment, Strong problem-solving and ownership mindset 📃 Skills: C#, .NET, Blazor, SQLServer, Azure, AzureFunctions, AzureDevOps, Agile 🏢 Description: We are looking for an experienced Senior .NET Developer to join a long-term project delivered for a well-established UK-based client from the insurance and reinsurance sector. You will become part of an international delivery team responsible for developing and modernizing business-critical applications as part of the client's ongoing migration to the Microsoft Azure ecosystem. 📍 100% Remote (Poland) 🚀 Start: Beginning of August 📅 6-month contract with possible extension 💼 B2B Requirements: Minimum 5 years of commercial experience as a .NET Developer Strong hands-on experience with C# and .NET Commercial experience with Blazor (or strong Full Stack experience with willingness to learn Blazor) Experience working with SQL Server Practical experience with Microsoft Azure Experience developing Azure Functions Experience working with Azure DevOps Very good English communication skills (minimum B2 ) Ability to work independently and proactively in an Agile environment Strong problem-solving skills and ownership mindset Nice to have: Experience in the insurance or financial services industry Experience working in distributed international teams Knowledge of Scrum or Kanban Experience with application modernization or cloud migration projects Familiarity with legacy application modernization Responsibilities: Design, develop, and deliver software solutions based on business and technical requirements Develop and maintain applications using .NET, Blazor, SQL Server, and Microsoft Azure Build and maintain Azure Functions and cloud-based services Participate in technical discussions and contribute to solution design Collaborate closely with developers, testers, architects, Product Owners, and business stakeholders Ensure high-quality, maintainable, and scalable code Take ownership of assigned user stories from development through delivery Support the modernization of legacy applications into the Azure ecosystem Participate in Agile ceremonies and work closely with distributed international teams We offer: Up to 110 PLN/h net on B2B 100% remote work 14-day invoice payment terms Private healthcare package Access to the MyBenefit cafeteria platform (including MultiSport and gift cards) Long-term cooperation with an international UK client Opportunity to work on large-scale Azure modernization projects Collaborative environment with experienced engineering teams and modern development practices

🏢 Summary: Oferta dla Senior .NET Developera obejmuje rozwój i utrzymanie autorskiej platformy ERP dla branży automotive, obsługującej sprzedaż na wielu rynkach europejskich. Rola koncentruje się na backendzie, integracjach REST/HTTP i InsERT nexo oraz automatyzacji procesów biznesowych. Współpraca jest głównie zdalna w modelu B2B, z okazjonalnymi spotkaniami w Warszawie. 🗂️ Requirements: Bardzo dobra znajomość .NET 6.0+, Doświadczenie w integracjach REST/HTTP API, Doświadczenie w rozwoju produkcyjnych systemów backendowych, Dobra znajomość SQL i relacyjnych baz danych, Samodzielna realizacja zadań od analizy do wdrożenia, Znajomość procesów CI/CD i konfiguracji pipeline’ów, Samodzielność i odpowiedzialność za produkt, Bardzo dobre umiejętności komunikacyjne w pracy z biznesem, Gotowość do rozpoczęcia współpracy najpóźniej w październiku 📃 Skills: .NET, REST, HTTP, SQL, PostgreSQL, CI/CD, GitLab, GitOps, Kubernetes, GCP, OpenTelemetry, InsERT, Rider 🏢 Description: Dla rozwijającej się firmy z branży Automotive poszukujemy doświadczonej osoby na stanowisko Senior .NET Developer. Będziesz pracować nad rozwojem autorskiej platformy ERP, która łączy dystrybutorów części samochodowych z kierowcami i mechanikami na 10 europejskich rynkach. Platforma obsługuje dziesiątki tysięcy transakcji miesięcznie i integruje się z największymi platformami e-commerce oraz dostawcami części samochodowych. Projekt obejmuje rozwój kluczowych funkcjonalności systemu oraz integrację z ekosystemem InsERT nexo, odpowiadającym za procesy księgowe i logistyczne. Istotnym elementem tej roli będzie rozwój integracji z systemami zewnętrznymi oraz projektowanie rozwiązań wspierających automatyzację procesów biznesowych. Lokalizacja: Zdalna (okazjonalne spotkania w biurze w Warszawie) Widełki: 18.000 - 26.000 netto + VAT miesięcznie na B2B W ramach pracy będziesz zajmować się m.in.: projektowaniem, rozwijaniem oraz utrzymaniem integracji pomiędzy autorskim systemem ERP a zewnętrznymi systemami biznesowymi, budowaniem i rozwijaniem mechanizmów wymiany danych opartych o REST API / HTTP API, rozwojem i utrzymaniem backendu autorskiej platformy ERP, projektowaniem oraz implementacją nowych funkcjonalności w środowisku .NET, udziałem w integracji platformy z ekosystemem InsERT nexo, analizą wymagań biznesowych i proponowaniem najlepszych rozwiązań, wdrażaniem zmian od etapu analizy aż do produkcji, współpracą z zespołem developerskim oraz osobami z warstwy biznesowej, dbaniem o jakość kodu oraz rozwój architektury systemu. Szukamy osoby, która posiada: bardzo dobrą znajomość .NET 6.0+, praktyczne doświadczenie z integracjami opartymi o REST/HTTP API, doświadczenie w budowie i rozwoju produkcyjnych systemów backendowych, dobrą znajomość SQL oraz relacyjnych baz danych (preferowany PostgreSQL), umiejętność samodzielnego realizowania zadań od analizy do wdrożenia, dobrą znajomość procesów CI/CD oraz doświadczenie w rozwijaniu lub konfiguracji pipeline'ów, umiejętność samodzielnej pracy i brania odpowiedzialności za tworzony produkt, bardzo dobre umiejętności komunikacyjne pozwalające na kontakt z osobami biznesowymi, nastawienie na bycie częścią zespołu i otwartość na feedback, gotowość do rozpoczęcia współpracy najpóźniej w październiku (warunek konieczny). Mile widziane: doświadczenie z InsERT nexo, znajomość Google Cloud Platform, doświadczenie z Kubernetes, doświadczenie z OpenTelemetry, doświadczenie z integracjami platform e-commerce (Allegro, eBay) oraz systemów płatności (PayPal, Adyen, Przelewy24), znajomość branży Automotive. Obecny stack technologiczny na projekcie: Backend: .NET Core 9 (wkrótce .NET 10), REST Api, PostgreSQL 15+, InsERT nexo (Subiekt, Rewizor, Gratyfikant), GitLab, GitOps, Kubernetes, Google Cloud Platform, OpenTelemetry, AI. Co otrzymasz? realny wpływ na architekturę oraz rozwój kluczowych systemów biznesowych, możliwość współtworzenia centralnego systemu ERP obsługującego sprzedaż na wielu rynkach europejskich, zatrudnienie na kontrakcie B2B, stabilną, długoterminową współpracę w firmie produktowej, możliwość pracy przy nowoczesnym produkcie rozwijanym w najnowszych technologiach, pracę głównie zdalną z okazjonalnymi wizytami w warszawskim biurze, nowoczesne środowisko pracy (Rider, narzędzia AI wspierające development), dużą samodzielność i wpływ na podejmowane decyzje techniczne, pracę w zespole nastawionym na rozwój produktu i wysoką jakość kodu.

🏢 Summary: Senior Backend Engineer role developing and maintaining C#/.NET desktop applications for manufacturing and testing environments. The position focuses on WPF/MVVM GUI development, hardware and instrument integration, automated testing, Python script integration, and stable parallel execution. 🗂️ Requirements: 5+ years of C#/.NET experience, WPF or similar GUI framework experience, MVVM experience, Async programming, multithreading, and thread-safety knowledge, Clean architecture and testable code design knowledge, MongoDB or similar database experience 📃 Skills: C#, .NET, WPF, MVVM, MongoDB, Python 🏢 Description: We are looking for a Senior Backend Enginee r to join a team developing advanced desktop applications for manufacturing and testing environments. This role is a good fit for someone who has strong experience with C#/.NET, enjoys solving complex technical problems. ✅ Your responsibilities: Develop and maintain C# / .NET desktop applications for manufacturing and testing systems Build GUI features using WPF / MVVM Work with hardware integration, instrument control and automated test execution Integrate Python-based test scripts into .NET applications Support parallel execution, thread safety and application stability Troubleshoot issues using logs, traces and system data 🧠 Our requirements: 5+ years of experience with C# / .NET Experience with WPF or similar GUI frameworks and MVVM Good understanding of async programming, multithreading and thread safety Understanding of clean architecture and testable code design Experience with MongoDB or similar databases 🌟 What we offer: Private healthcare Real influence on technical decisions Opportunity to work on a modern AI / ML product platform

🏢 Summary: Long-term remote contract for an experienced .NET Developer to design, build, and improve business-critical enterprise applications for an international project. The role combines hands-on full-stack development, solution design, technical decision-making, and support for testing, releases, and deployments, with extension potential of up to four years. 🗂️ Requirements: 4+ years of professional software development experience, 2+ years of enterprise .NET development experience, Experience with complex, business-critical systems, Knowledge of layered architecture, Knowledge of UML, Full software development lifecycle experience, Scrum and Agile delivery familiarity, English proficiency at B2 level or higher, Relevant software development certification, ICT-related bachelor’s degree or equivalent 📃 Skills: .NET, UML, Scrum, Agile 🏢 Description: We are looking for experienced .NET Developers to build and enhance business-critical applications for a large international organisation. The role combines hands-on development with solution design and technical decision-making. Your responsibilities Design and develop enterprise applications using .NET Translate business needs into effective technical solutions Work across data, business logic and user interface layers Improve application performance, security and quality Support testing, releases and deployments Provide technical guidance and maintain documentation What we are looking for (must have): 4+ years of professional software development experience 2+ years in enterprise .NET development Experience with complex, business-critical systems, ideally in HR, finance or asset management Knowledge of layered architecture and UML Experience with the full software development lifecycle Familiarity with Scrum and Agile delivery English at B2 level or higher Relevant software development certification ICT-related bachelor’s degree or equivalent Offer Long-term contract with the possibility of extension for up to four years Stable international project Remote working model No security clearance required