Senior C# Developer for Microsoft 365

Veeam Software seeks an experienced C# Developer to join its Warsaw team. This position is designed for professionals who take pride in building dependable, thoughtfully designed software. Role overview The team emphasizes collaboration and values technical excellence. Developers here work together to achieve high-quality outcomes and maintain a supportive environment. What you will do Contribute to the design and development of software using C# Focus on delivering reliable and maintainable solutions Work closely with colleagues to achieve shared goals Requirements Professional experience with C# development Commitment to quality and attention to detail Interest in collaborative problem-solving

Veeam Software seeks a Senior C# Developer based in Warsaw, Poland. This position centers on enhancing data management and cloud backup products. Collaboration and delivering clear results for clients are core values for the team. Key responsibilities Design and implement features for data management and cloud backup solutions using C# Collaborate with other developers to expand and strengthen product functionality Share ideas and participate in code reviews and team discussions Requirements Extensive hands-on experience with C# development Comfort working as part of a collaborative team Genuine interest in data management and cloud technologies

At Veeam, we are committed to being the Data and AI Trust Company, empowering organizations to secure and comprehend their data and AI assets. As the leading provider in data resilience and security posture management, we are uniquely positioned to address the convergence of identity, data security, and AI risk. With our headquarters in Seattle and a presence in over 30 countries, Veeam proudly protects more than 550,000 customers globally, ensuring their businesses operate smoothly. Join us on our journey as we move forward together, fostering growth, learning, and making a significant impact for some of the world’s most prominent brands.About the RoleWe are seeking a motivated Junior C# Developer to become a key part of our team focused on Veeam Backup and Replication, along with its extensions.What You’ll DoDevelop and design REST APIs for Veeam Backup & Replication.Create new products while providing support for existing features.Engage in individual and team development of components and overall product architecture.Technologies We Use:C#, .Net 10, Windows/Linux, MS SQL, PostgreSQL, Multithreading.

Veeam is recognized as the Data and AI Trust Company, dedicated to empowering organizations to fully comprehend, secure, and maintain the resilience of their data and AI systems. As a leader in data resilience and security posture management, Veeam is designed for the convergence of identity, data, security, and AI risk management. With its headquarters in Seattle and operations in over 30 countries, Veeam safeguards the data of more than 550,000 customers globally, who rely on Veeam to ensure their business continuity. Join us in our mission to advance fearlessly, fostering growth, learning, and making a significant impact for some of the world's largest brands.About the RoleWe are seeking a skilled C# Developer to join our team, where you will play a pivotal role in enhancing the backend of Veeam Backup for Hypervisors, improving data protection and fostering business resilience.What You'll DoDesign and implement business logic for virtualization products (RHV, Nutanix, Proxmox VE, etc.)Develop new functionalities and enhance existing featuresImplement significant functionalities across various components of the productContribute to the individual development of components and the overall architecture of the product

Join our innovative team at inetum2 as a JVM Software Engineer / C Developer. In this role, you will leverage your expertise in Java Virtual Machine (JVM) and C programming to design, develop, and maintain high-quality software solutions.We are looking for someone passionate about technology, who thrives in a collaborative environment and is eager to tackle complex challenges. You will work closely with cross-functional teams to deliver robust applications that meet our clients' needs.

We are seeking a highly skilled and motivated Senior Full Stack Developer proficient in Python 3 and C++. In this role, you will work closely with our engineering and development teams to design, implement, and maintain robust software solutions that meet our clients' needs.Your expertise will help in driving innovation and developing new features while ensuring the performance, quality, and responsiveness of applications.

Sperasoft seeks a C++ Developer with strong Unreal Engine 4 or 5 skills to join the team building AAA game titles. This remote role is based in Warsaw, Masovian Voivodeship, Poland. Work alongside experienced engineers and contribute to high-profile projects aimed at major gaming platforms. Key responsibilities Design and implement features across gameplay, AI, and engine systems using Unreal Engine 4 or 5. Collaborate with team members from various disciplines throughout the development cycle. Assist with deployment to major platforms and stores such as Sony, Microsoft, and Nintendo. Participate in architectural planning, design new systems and modules, and prototype features. Optimize code for performance to ensure smooth player experiences. Engage in all phases of game development, from early design through to release.

Join Veeam Software as a Software Developer in Test, where you will be at the forefront of ensuring the quality and reliability of our products. You will work in a dynamic environment, utilizing your expertise in Python or C# to develop automated tests and enhance our testing frameworks.

JetBrains is seeking an AI Lead focused on integrating artificial intelligence into the C++ ecosystem. This role shapes how AI features enhance C++ development tools, directly impacting the way engineers write and maintain code. Key responsibilities Lead initiatives that embed AI capabilities into JetBrains C++ products Collaborate with engineering teams to design and implement AI-driven solutions for software development workflows Help set the direction for AI in C++ tooling at JetBrains Locations This position is open in Amsterdam, Belgrade, Berlin, Limassol, London, Madrid, Munich, Paphos, Prague, remote (Germany), Warsaw, and Yerevan.

Join our dynamic team at Veeam Software as a Quality Assurance Automation Engineer specializing in C#. In this crucial role, you will be responsible for designing, developing, and executing automated tests to ensure the highest quality of our software products. Your expertise will help us maintain our reputation for excellence and reliability in the industry.

CD Projekt Red is hiring a Software Engineer (C++) to focus on online and multiplayer features at their Warsaw studio. This role is part of the engineering department and helps shape the multiplayer experience for players around the world. Role overview This position centers on developing and refining systems that power multiplayer gameplay. Collaboration is key, as the engineer will work alongside other developers and team members to build engaging online features. What you will do Collaborate with engineers and other team members to develop and enhance online and multiplayer systems. Use C++ to improve game performance and system efficiency. Design and implement new features that support immersive multiplayer experiences. The team Work with a group of experienced professionals dedicated to creating memorable gaming experiences. The team values technical expertise, creativity, and a drive to advance multiplayer gaming.

Sperasoft seeks a Rendering Developer to strengthen the visual quality of its games. This is a remote role based in Warsaw, Masovian Voivodeship, Poland. The position centers on building advanced graphics engine features for both PC and console titles. Regular collaboration with engineers, artists, game designers, and QA specialists is part of daily work. Key responsibilities Design and develop graphics engine components for PC and console platforms. Implement and optimize rendering systems, addressing both high-level and low-level needs. Write clean, efficient, and maintainable C++ code. Contribute to technical decisions and influence the rendering architecture. Participate in all stages of game development, from prototyping through release. Mentor and support other engineers as needed.

Join Tietoevry as a Junior Software Engineer specializing in C language, where you'll contribute to innovative telecommunications solutions. Be part of a dynamic team that pushes the boundaries of technology and drives growth.

Join altersolutions as a .NET Developer and be part of a dynamic team in Warsaw, where you will contribute to exciting projects and develop innovative software solutions. We seek passionate developers who thrive on creativity and collaboration.

At Rydoo, we strive to simplify expense management, allowing individuals to concentrate on what truly matters rather than drowning in receipts. With over a million users relying on us, we facilitate faster and smarter expense submission, approval, and control.In line with this mission, Semine has been developing AI technologies since 2015 to eliminate the tedious and repetitive tasks in accounting, empowering finance teams to work more efficiently.In July 2025, Semine united with Rydoo to revolutionize the future of financial automation. Together, we're crafting a comprehensive, AI-driven platform designed to streamline accounts payable and expense management, enabling businesses to operate with greater simplicity, speed, and intelligence.Our international team exceeds 200 talented individuals who believe that innovative technology should enhance the quality of life. If you have visionary ideas and a desire to create impactful solutions, you will find a welcoming environment here.

Role overview Alarm.com is looking for a Software Engineer skilled in C# and .NET to join the team at the EBS Warsaw office. The group focuses on building technology that enhances security and automation for both residential and commercial settings. What you will do Develop and maintain software using C# and .NET frameworks Create and support solutions that enable security and automation features Participate in all phases of the software development lifecycle, from design and coding to testing and deployment Location This role is based onsite in Warsaw, Poland, at the EBS office.

Join our team as a .NET Developer and be part of our dynamic tech environment where innovation and collaboration thrive. In this role, you will develop high-quality software solutions and contribute to exciting projects that impact our clients positively.

About the RoleJoin our dynamic team at margo-group as a Regular .NET Developer, where you will play a pivotal role in the development and maintenance of our core card payment systems. You will be involved in everything from transaction authorization and settlement to integrations with external payment services, catering to hundreds of thousands of transactions daily. Ensuring optimal performance, availability, and security is our top priority.Work Model: This is a remote-first position, with scheduled on-site team meetings twice a month in Warsaw.Key Responsibilities- Develop and maintain .NET applications within the card payment sector.- Design and implement new functionalities in compliance with business and regulatory requirements.- Integrate systems with external services using REST, SOAP, and messaging queues.- Optimize application performance, availability, and security.- Collaborate with Analysts, Architects, and QA teams in an Agile/Scrum environment.- Participate in SIT/UAT testing, code reviews, and the preparation of technical documentation.Required Skills- Proven commercial experience with C# and .NET (Framework/Core).- Familiarity with ASP.NET Core, Angular, and WebAPI.- Knowledge of Entity Framework, LINQ, and Dapper.- Proficiency with SQL Server (T-SQL) and query optimization techniques.- Understanding of SOLID principles and design patterns.- Experience writing unit tests (xUnit/NUnit).- Knowledge of system integrations (REST, SOAP, JSON, XML).- Experience working in an Agile environment.- Familiarity with Git, CI/CD, and TeamCity.Language Requirements- Polish: Native or C2 level (required).- English: Professional level for technical documentation.Nice to Have- Experience in the card payments/payment processing domain.- Knowledge of Docker and Kubernetes.- Experience with high-availability or complex distributed systems.

Join SKELAR, a pioneering Ukrainian venture builder committed to crafting international tech businesses. Working alongside our co-founders, we assemble talented teams aimed at achieving victory in global markets.Currently, SKELAR boasts a diverse portfolio of businesses across various sectors such as EdTech and marketplaces. Our startups are consistently recognized among Ukraine's top startups and product companies, achieving high rankings in the PlayStore and developing platforms utilized by millions. Our businesses have been featured in renowned media outlets like TechCrunch and Wired.We take pride in a robust team of over 1,000 experts with exceptional expertise and ambitious goals. Our people are our most valuable asset, and we strive to build businesses with the finest talents available in the market.We are currently seeking a Strong Middle/Senior Android Developer.PawChamp is a mobile application and online platform designed for pet parents—dog owners—providing them with resources to train their pets and learn more about dog care through 24/7 expert chats, our AI companion Pawchie, and educational materials developed with canine professionals. We deliver personalized daily lessons covering all aspects of dog training from basic commands to behavioral problem-solving. Our strategic goal is to become a leader in the global online dog training market, catering to all needs of pet parents and their dogs beyond just training.Recognized as Product of the Day on Product Hunt in October 2025.PlayStore rating: 4.2Intro video about the product: Watch hereChallenges awaiting you:- Support and enhance existing functionality; - Implement new features while adhering to agreed architectural approaches; - Ensure product stability and high quality through Unit and Integration testing; - Collaborate closely with a cross-functional team: from discussing logic with the Product Owner to aligning contracts with Backend and refining UI/UX with designers; - Involve in task decomposition, estimation, and collaborative sprint planning; - Actively influence improvements in workflows, technology stack selection, and development approaches within the team;What we value:Must have:4+ years of experience in Android development...