Senior .NET Developer with Fintech

🏢 Summary: Senior .NET Developer role focused on building and enhancing a cloud-native embedded finance platform in a regulated FinTech environment. The position involves designing, developing, and deploying scalable, secure features using a modern tech stack while ensuring high performance and reliability in production. You will work across backend and frontend technologies, contributing to CI/CD, cloud infrastructure, and event-driven systems. 🗂️ Requirements: 5+ years of software development experience, Strong OOP and system design skills, Hands-on experience with .NET and C#, Hands-on experience with Angular, Understanding of software testing concepts, Experience with cloud-native architectures, Experience with CI/CD and DevOps practices, Experience with relational databases, Experience with NoSQL databases, Knowledge of performance, security, and availability principles, Experience in FinTech, payments, banking, or regulated environments, Upper-Intermediate English or higher 📃 Skills: C#, .NET, Angular, AWS, CI/CD, Docker, Kubernetes, Kafka, RabbitMQ, Datadog, SQL, NoSQL, OOP, DDD 🏢 Description: Looking to take your .NET expertise to the next level while working on high-impact FinTech solutions? This role offers the chance to contribute to scalable, cloud-native systems that empower thousands of businesses worldwide. We’re seeking a Senior .NET Developer to join our team, collaborating with talented engineers, product managers, and designers to deliver innovative financial technology. At Sigma Software, we work with some of the most forward-thinking companies in the industry. This opportunity will let you grow professionally while making a tangible difference in a fast-paced, regulated environment. Customer Our customer is a leading FinTech company providing embedded financing solutions for platforms and marketplaces. Their mission is to enable businesses to offer flexible credit products to customers, helping SMEs access funding quickly and efficiently. The customer is recognized for innovation in embedded finance, serving thousands of businesses globally and partnering with major platforms. They operate in a regulated environment with a strong focus on scalability, performance, and security. Project The project involves enhancing and expanding customer’s embedded finance platform, which integrates directly into partner services to deliver fast, flexible funding to SMEs. You’ll work on a modern tech stack, building features that improve customer and partner experiences while ensuring reliability in production. Key Technologies: C#, .NET Core, Angular 18, AWS, CI/CD, Docker/Kubernetes, Kafka/RabbitMQ, Datadog, relational & NoSQL databases. Responsibilities Design, build, and deliver features and projects across C#, .NET Core, and Angular stack Write clean, maintainable, and well-tested code (unit/integration/e2e) Take ownership of features from requirements breakdown to deployment Deploy and monitor services in AWS cloud-native environments Handle production issues and incidents with accountability Collaborate with Product, Design, and Engineering teams in Agile practices Contribute to continuous improvement of systems and processes Requirements 5+ years of experience in software development with strong OOP and system design skills Solid hands-on experience with .NET (C#) and Angular Understanding of software testing concepts and practices Expertise in cloud-native and DevOps practices (CI/CD, automation, monitoring) Experience with relational and NoSQL databases Knowledge of non-functional requirements (performance, security, availability) Proven experience in FinTech, payments, banking, or regulated financial environments Upper-Intermediate English level or higher Will be a plus Experience with Docker/Kubernetes Familiarity with event-driven architectures (Kafka, RabbitMQ) Proficiency with observability tools (Datadog or similar) Knowledge of domain-driven design (DDD) and complex domain modeling Personal profile Growth mindset, curiosity, and proactivity Strong problem-solving skills balancing complexity and simplicity Feedback-oriented, open to giving and receiving constructive input Ownership & accountability in delivering commitments Team player with strong collaboration skills Adaptability to changing priorities Excellent communication skills across disciplines

🏢 Summary: Senior .NET Developer role focused on building and enhancing a scalable, cloud-native embedded finance platform in a regulated FinTech environment. The position involves designing and delivering full-stack features using .NET and Angular while ensuring high performance, security, and reliability in AWS. You will work on production-grade systems powering financial solutions for global businesses. 🗂️ Requirements: 5+ years of software development experience, Strong OOP and system design knowledge, Hands-on experience with C# and .NET, Hands-on experience with Angular, Understanding of software testing concepts and practices, Experience with cloud-native and DevOps practices, Experience with CI/CD, automation, and monitoring, Experience with relational databases, Experience with NoSQL databases, Knowledge of performance, security, and availability principles, Experience in FinTech, payments, banking, or regulated financial environments 📃 Skills: C#, .NET, Angular, AWS, CI/CD, SQL, NoSQL, OOP, DevOps, Testing 🏢 Description: Looking to take your .NET expertise to the next level while working on high-impact FinTech solutions? This role offers the chance to contribute to scalable, cloud-native systems that empower thousands of businesses worldwide. We’re seeking a Senior .NET Developer to join our team, collaborating with talented engineers, product managers, and designers to deliver innovative financial technology. At Sigma Software, we work with some of the most forward-thinking companies in the industry. This opportunity will let you grow professionally while making a tangible difference in a fast-paced, regulated environment. Customer Our customer is a leading FinTech company providing embedded financing solutions for platforms and marketplaces. Their mission is to enable businesses to offer flexible credit products to customers, helping SMEs access funding quickly and efficiently. The customer is recognized for innovation in embedded finance, serving thousands of businesses globally and partnering with major platforms. They operate in a regulated environment with a strong focus on scalability, performance, and security. Project The project involves enhancing and expanding customer’s embedded finance platform, which integrates directly into partner services to deliver fast, flexible funding to SMEs. You’ll work on a modern tech stack, building features that improve customer and partner experiences while ensuring reliability in production. Key Technologies: C#, .NET Core, Angular 18, AWS, CI/CD, Docker/Kubernetes, Kafka/RabbitMQ, Datadog, relational & NoSQL databases. Responsibilities Design, build, and deliver features and projects across C#, .NET Core, and Angular stack Write clean, maintainable, and well-tested code (unit/integration/e2e) Take ownership of features from requirements breakdown to deployment Deploy and monitor services in AWS cloud-native environments Handle production issues and incidents with accountability Collaborate with Product, Design, and Engineering teams in Agile practices Contribute to continuous improvement of systems and processes Requirements 5+ years of experience in software development with strong OOP and system design skills Solid hands-on experience with .NET (C#) and Angular Understanding of software testing concepts and practices Expertise in cloud-native and DevOps practices (CI/CD, automation, monitoring) Experience with relational and NoSQL databases Knowledge of non-functional requirements (performance, security, availability) Proven experience in FinTech, payments, banking, or regulated financial environments Upper-Intermediate English level or higher Will be a plus Experience with Docker/Kubernetes Familiarity with event-driven architectures (Kafka, RabbitMQ) Proficiency with observability tools (Datadog or similar) Knowledge of domain-driven design (DDD) and complex domain modeling Personal profile Growth mindset, curiosity, and proactivity Strong problem-solving skills balancing complexity and simplicity Feedback-oriented, open to giving and receiving constructive input Ownership & accountability in delivering commitments Team player with strong collaboration skills Adaptability to changing priorities Excellent communication skills across disciplines

🏢 Summary: Senior Software Engineer role focused on developing and maintaining a complex enterprise .NET platform, combining backend development, production troubleshooting, and performance optimization. The position involves working on identity-related systems and improving architecture, reliability, and code quality within a large-scale environment. The engineer will contribute to technical decisions and future platform evolution. 🗂️ Requirements: 5+ years commercial experience with C# and .NET, Strong knowledge of ASP.NET Core, Experience with asynchronous programming, Experience with dependency injection, Hands-on experience with Entity Framework Core, Strong understanding of SQL Server, Experience with query optimization, Experience with OAuth2, Experience with OpenID Connect, Experience with JWT, Experience supporting and troubleshooting production systems, Fluent English 📃 Skills: C#, .NET, ASP.NET, EntityFramework, SQLServer, OAuth2, OpenIDConnect, JWT, IdentityServer, Duende, ActiveDirectory, AzureAD, MicrosoftGraph, Quartz.NET, SignalR, Playwright, AzureDevOps, CI/CD 🏢 Description: We are looking for an experienced Senior Software Engineer to develop and maintain a complex enterprise .NET platform used by global organizations. This role combines backend development , production troubleshooting , performance optimization , and work on identity-related systems . 💼 Responsibilities: Design, develop, and maintain backend services built with C# and .NET Investigate and resolve complex production issues and customer-reported problems Optimize application performance, database queries, and system reliability Collaborate with Product, Support, and Engineering teams on technical solutions Improve architecture, code quality, and engineering standards Participate in technical discussions and contribute to future platform development ✅ Requirements: 5+ years of commercial experience with C# and .NET Strong knowledge of ASP.NET Core and modern .NET applications Experience with asynchronous programming and dependency injection Hands-on experience with Entity Framework Core Good understanding of SQL Server, query optimization, and database performance Experience with OAuth2, OpenID Connect, JWT Experience supporting and troubleshooting production systems Fluent English communication skills 🌟Nice to have: Experience with IdentityServer / Duende IdentityServer Understanding of Active Directory, Azure AD or Microsoft Graph Hands-on experience with Quartz.NET or similar scheduling frameworks Familiarity with SignalR, Playwright, Azure DevOps and CI/CD pipelines 🎁 We offer: Work on a mature enterprise product used globally Influence technical decisions and platform evolution Private healthcare Life insurance Multisport Opportunity to work with modern .NET technologies and large-scale systems

🏢 Summary: Senior .NET Developer role focused on building and maintaining secure, high-performance online banking solutions in a hybrid work model. The position involves developing new backend features, optimizing databases, and managing containerized applications in an Agile, distributed environment. The role also includes ensuring code quality, supporting production systems, and contributing to secure payment functionalities. 🗂️ Requirements: Minimum 4 years of experience in IT systems development, Strong hands-on experience with .NET, Strong knowledge of PostgreSQL, Strong knowledge of MS SQL, Experience with Docker, Experience with Kubernetes, Practical understanding of Agile methodology, Ability to develop new features and maintain existing systems, Ability to work independently in distributed teams 📃 Skills: .NET, C#, PostgreSQL, MS SQL, SQL, Docker, Kubernetes, Agile, Elixir, Sorbnet 🏢 Description: Innovate online banking and join the team as a Senior .NET Developer! Warsaw-based opportunity with hybrid work model (2 times in the office/month). As a Senior .NET Developer , you will be working for our client, one of the leaders in online banking, supporting the development and maintenance of secure, high-performance financial solutions. You’ll be contributing to a team responsible for building and enhancing banking functionalities, ensuring reliability and innovation. Working in a distributed Agile environment, you’ll play a key role in both implementing complex backend logic and actively collaborating with cross-functional teams. Your main responsibilities: Design and develop new features in .NET 8 Implement and optimize SQL-based data access Build and maintain containerized applications using Docker and Kubernetes Collaborate with distributed teams in an Agile environment Participate in the development of secure payment solutions Share knowledge and support less experienced team members Ensure code quality through code reviews and testing Maintain existing functionalities and resolve production issues Manage your own time and responsibilities while working remotely You're ideal for this role if you have: Strong experience in developing IT systems (min. 4 years of experience) Solid hands-on experience with .NET Strong knowledge of PostgreSQL and MS SQL Practical understanding of Agile software development Excellent communication and collaboration skills in distributed teams Ability to work independently and manage your time effectively Experience in developing new features and maintaining existing ones A passion for software development and continuous learning Experience with Docker and Kubernetes Nice to have: Knowledge of banking domain such as payments and transactions (e.g. Elixir, Sorbnet)

🏢 Summary: Long-term project for a Senior/Expert .NET Developer focused on backend and API development within enterprise banking systems. The role involves developing and optimizing software solutions, working with legacy code, and providing technical leadership and mentorship. The position emphasizes high-quality standards, collaboration, and code excellence in a complex financial environment. 🗂️ Requirements: Strong knowledge of C#, Strong knowledge of .NET framework, Expertise in ASP.NET Core, Experience in API development, Experience with SQL Server design and development, Ability to analyze and troubleshoot legacy code, Solid understanding of OOP principles, Knowledge of software engineering best practices 📃 Skills: C#, .NET, ASP.NET, SQL, T-SQL, Git, Jenkins, Angular, HTML, CSS, JavaScript, Visual Studio, Postman, Swagger, Bitbucket, Bootstrap, SQL Server 🏢 Description: We’re looking for an Expert/Senior .NET Developer to join a long-term project for a leading client in the banking industry. Project Type: Enterprise banking systems – backend & API development, code optimization, and mentorship Responsibilities: Design, develop, and maintain software solutions Analyze, refactor, and troubleshoot legacy code Conduct code reviews and uphold high-quality standards Collaborate with QA and Business Analysts Mentor junior developers and provide technical leadership Must-Have Experience: Strong knowledge of C# and the .NET framework Expertise in ASP.NET Core and API development Experience with SQL Server (design & development) Ability to work with and troubleshoot legacy code Solid understanding of OOP and software engineering best practices Nice-to-Have: Familiarity with Git, Jenkins, and testing frameworks Understanding of cloud concepts & web security best practices Knowledge of frontend technologies (Angular, HTML, CSS, JavaScript) Tools & Tech Stack:Visual Studio, Postman, Swagger, Bitbucket, SQL Server Management Studio, T-SQL, Bootstrap (or similar)

🏢 Summary: Mid-Level .NET Developer role focused on building and maintaining online banking applications in a hybrid work model. The position involves developing scalable financial systems, integrating APIs, and ensuring high code quality in an Agile environment. You will contribute to digital transformation initiatives within modern fintech projects. 🗂️ Requirements: Minimum 3 years of experience with C# and .NET (Core, 5/6, Framework), Strong experience with MSSQL, Experience implementing REST APIs, Experience writing unit tests using xUnit and xRay, Knowledge of message queuing systems (RabbitMQ or Kafka), Knowledge of OOP and SOLID principles, Basic knowledge of Kubernetes and Docker, Experience with CI/CD tools, Familiarity with Agile/Scrum methodology, Communicative English proficiency, Legal right to work in the European Union 📃 Skills: C#, .NET, .NETCore, .NET5, .NET6, .NETFramework, MSSQL, REST, xUnit, xRay, RabbitMQ, Kafka, Kubernetes, Docker, OOP, SOLID, CICD, Bitbucket, JIRA, TeamCity, Agile, Scrum 🏢 Description: Unleash Innovation in Financial Technology — Shape the Future of Online Banking! Łódź-based opportunity with a hybrid work model (2 days in the office per month) As a Mid-Level .NET Developer , you will be working for our client, a leader in online banking, on cutting-edge financial technology projects designed to enhance user experience and system efficiency. Join a fast-paced environment where your expertise drives digital transformation and financial innovation. Your main responsibilities: Develop and maintain applications using C#, .NET Core Implement and integrate RESTful APIs Write unit tests to ensure code quality Follow and apply design patterns and best practices such as OOP and SOLID Work with MSSQL databases Collaborate with cross-functional teams using tools like Bitbucket, JIRA, and TeamCity Participate in Agile/Scrum meetings and contribute to sprint planning and review Troubleshoot and resolve complex technical issues You're ideal for this role if you have: At least 3 years of experience with C#, .NET Core, .NET 5/6, or .NET Framework Solid experience with MSSQL Basic knowledge of Kubernetes and Docker Experience in implementing REST APIs Proficiency in writing unit tests with xUnit and xRay Experience with message queuing systems (e.g., RabbitMQ, Kafka) Knowledge of design patterns and best practices (OOP, SOLID) Familiarity with Agile/Scrum methodologies Proficiency with CI/CD tools Strong problem-solving skills and attention to detail It is a strong plus if you have: (optional) Basic knowledge of COBOL Knowledge of WCF, WinForms Language required for the role: Communicative proficiency in English Communicative proficiency in Polish Eligibility to work in Europe: Only candidates with an existing legal right to work in the European Union will be considered for this role. #MAKEYourCareerBETTER Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.

🏢 Summary: Senior .NET Developer role focused on building and maintaining secure, high-performance online banking solutions in a distributed Agile environment. The position involves developing backend features in .NET 8, optimizing SQL-based data access, and working with containerized applications. Hybrid work model with strong emphasis on reliability, security, and collaboration. 🗂️ Requirements: Minimum 4 years of experience in IT system development, Hands-on experience with .NET, especially .NET 8, Strong knowledge of PostgreSQL, Strong knowledge of MS SQL, Experience with Docker, Experience with Kubernetes, Practical experience in Agile software development, Experience in developing new features and maintaining existing systems, Good command of Polish, Legal right to work in the European Union 📃 Skills: .NET, C#, PostgreSQL, MSSQL, SQL, Docker, Kubernetes, Agile 🏢 Description: Ignite digital innovation — shape the future of online banking! Warszawa-based opportunity with hybrid work model (2 days in the office/month, up to 4 remote days/week). As a Senior .NET Developer , you will be working for our client, a leader in online banking, supporting the development and maintenance of secure, high-performance financial solutions. You’ll join a dynamic team dedicated to building cutting-edge banking functionalities, ensuring top-tier reliability and innovation. Operating within a distributed Agile environment, you’ll play a pivotal role in implementing complex backend logic while collaborating seamlessly across teams. This is your chance to contribute to transformative financial technology and accelerate your career growth. Your main responsibilities: Design and develop new features in .NET 8 to enhance banking solutions. Implement and optimize SQL-based data access for performance and security. Build and maintain containerized applications using Docker and Kubernetes. Collaborate with distributed teams within an Agile framework. Participate in the development of secure payment solutions. Share knowledge and mentor less experienced team members. Ensure code quality through reviews and testing. Maintain existing functionalities and address production issues. Manage your time effectively while working remotely. You're ideal for this role if you have: At least 4 years of experience in IT system development. Solid hands-on experience with .NET (especially .NET 8). Strong knowledge of PostgreSQL and MS SQL. Practical understanding of Agile software development. Excellent communication and collaboration skills in distributed teams. Ability to work independently and manage your responsibilities. Experience developing new features and maintaining existing ones. Passion for software development and continuous learning. Experience with Docker and Kubernetes. It is a strong plus if you have: (optional) Certifications in relevant technologies. Experience with financial or payment systems. Language Required for the role: Good command of Polish. Eligibility to work on this role: Only candidates with an existing legal right to work in the European Union will be considered for this role. #MAKEYourCareerBETTER Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.

🏢 Summary: Senior .NET + Angular Developer role focused on building and modernizing cloud-native financial systems using containerized microservices. The position involves designing scalable backend services, dynamic frontends, and leading Kubernetes-based deployments within a DevOps-driven environment. You will contribute to migrating legacy systems to a modern, resilient architecture with strong emphasis on clean code and automation. 🗂️ Requirements: 5+ years of experience in software engineering, Strong mastery of .NET (C#), Strong experience with Angular (v12+), Practical experience with Kubernetes, Experience building and running containerized applications, Proficiency in SQL Server or relational databases, Experience with database schema design and performance tuning, Knowledge of CI/CD practices, Understanding of TDD and SOLID principles, Fluent professional English 📃 Skills: .NET, C#, Angular, Kubernetes, SQL, SQLServer, CI/CD, TDD, SOLID, Azure, AWS, EKS, AKS, Kafka, Helm, Terraform, Microservices, Docker 🏢 Description: The Opportunity We are representing an established international financial institution currently undergoing a massive shift toward cloud-native architecture. While many firms talk about "digital transformation," this team is actively dismantling legacy monoliths and rebuilding them as high-performance, containerized microservices. We are looking for a Senior .NET + Angular Developer who doesn't just "use" Kubernetes but understands how to build and scale applications within a modern orchestration ecosystem. This is a role for an engineer who values clean code, architectural integrity, and the power of automated, scalable infrastructure. Your Impact Architect & Build: Design and develop robust backend services using .NET 8/Core and dynamic, responsive frontends in Angular. Cloud-Native Excellence: Take a lead role in deploying and managing services within Kubernetes , ensuring our applications are resilient, observable, and scalable. Database Engineering: Design efficient schemas and optimize complex queries within SQL environments to handle high-frequency financial data. Modernize the Stack: Actively participate in the migration of services to a containerized environment, advocating for best practices in CI/CD and DevOps. Collaborate: Work within a cross-functional team of high-caliber engineers, participating in deep-dive code reviews and architectural workshops. Your Technical Profile The Core: Extensive experience (5+ years) in software engineering with a strong mastery of .NET (C#) and Angular (v12+). The K8s Edge: Proven experience working with Kubernetes . You should be comfortable with pods, services, deployments, and understanding how your code behaves in a containerized environment. Data Mastery: Strong proficiency in SQL Server or similar relational databases, including performance tuning and schema design. Quality First: A mindset focused on TDD, Clean Code, and SOLID principles. Communication: Fluent professional English (written and spoken) is essential for collaboration with our global teams. Preferred (Nice-to-Have) Experience with Azure or AWS (EKS/AKS). Knowledge of Kafka or other message brokers for event-driven architecture. Familiarity with Helm charts or Terraform (IaC). What’s in it for You? Hybrid Flexibility: Work from the comfort of your home anywhere in Poland, with only two scheduled visits per month to our modern hub in Łódź for team integration and high-level strategy sessions. Premium Tech Stack: No "maintenance only" projects. You will work on greenfield features and modern cloud migrations. Stability & Growth: The security of an established enterprise with the agile mindset of a tech-forward team. Streamlined Recruitment: A transparent, technical process that respects your time.

🏢 Summary: Senior .NET Developer role focused on designing, extending, and modernising critical banking and securities systems in a fully remote B2B model. The position involves full-stack development, system integration, and cloud scaling within distributed, business-critical environments. The role requires close collaboration with business stakeholders and ownership of end-to-end application delivery. 🗂️ Requirements: 5+ years experience as .NET / C# Developer, Experience in banking or investment banking sector, Full-stack development experience, Knowledge of SOLID design principles, Experience with document-based databases, Experience with event-driven messaging frameworks, Experience with unit and integration testing, End-to-end application development experience, Ability to work during UK business hours, Based in Poland 📃 Skills: .NET, C#, MongoDB, SOLID, Messaging, UnitTesting, IntegrationTesting, Docker, Kubernetes, Cloud 🏢 Description: Work model: 100% remote (candidates must be based in Poland) Contract type: B2B Industry: Banking / Investment Banking We are looking for an experienced Senior .NET Developer to join a distributed engineering team working on critical banking systems. The role focuses on extending and modernising applications used across securities and banking operations, with a strong emphasis on system design, scalability, and cloud transformation. You will work end-to-end on business-critical systems, closely collaborating with Business Analysts, without a separate QA team. A solid background in banking or financial services is essential. Main Responsibilities: Design, develop, and extend .NET-based systems supporting multiple banking entities Contribute to the integration of securities and core banking platforms Support and enhance a portfolio of ~17 applications across product control and risk management Work with an in-house development framework in a full-stack capacity Participate in scaling applications for cloud-based, containerized environments Collaborate closely with business stakeholders to deliver robust solutions Ensure high code quality through unit and integration testing Key Requirements: 5+ years of professional experience as a .NET / C# Developer Hands-on experience in the banking or investment banking sector (mandatory) Full-stack development experience (backend-focused, frontend included) Strong understanding and practical application of SOLID design principles Experience with document-based databases (e.g. MongoDB) Experience with event-driven / event-based messaging frameworks Solid knowledge of unit and integration testing Experience working end-to-end on applications (development, testing, support) Ability to work independently in a fast-paced, regulated environment Availability during UK business hours Nice to Have: Experience with cloud platforms and application migration to cloud Experience with container technologies (e.g. Docker, Kubernetes) Exposure to systems such as Murex or large in-house banking platforms Background in securities, risk, or product control systems Other Details: This role is 100% remote with candidates required to be located in Poland. The contract is on a B2B basis within the banking and investment banking industry.

🏢 Summary: Senior .NET Developer role focused on designing, extending, and modernizing critical banking systems within securities and core banking domains. The position involves full-stack development, system integration, and cloud scaling in a distributed team without a separate QA function. Work includes end-to-end ownership of business-critical applications in a regulated investment banking environment. 🗂️ Requirements: 5+ years experience with .NET and C#, Hands-on experience in banking or investment banking, Full-stack development experience, Strong knowledge of SOLID principles, Experience with document-based databases, Experience with event-driven messaging frameworks, Knowledge of unit and integration testing, End-to-end application development experience, Ability to work independently in regulated environments, Availability during UK business hours, Poland-based residency 📃 Skills: .NET, C#, MongoDB, SQL, REST, Microservices, Docker, Kubernetes, Azure, UnitTesting, IntegrationTesting, EventDriven, Git 🏢 Description: Work model: 100% remote (candidates must be based in Poland) Contract type: B2B Industry: Banking / Investment Banking We are looking for an experienced Senior .NET Developer to join a distributed engineering team working on critical banking systems. The role focuses on extending and modernising applications used across securities and banking operations, with a strong emphasis on system design, scalability, and cloud transformation. You will work end-to-end on business-critical systems, closely collaborating with Business Analysts, without a separate QA team. A solid background in banking or financial services is essential. Main Responsibilities: Design, develop, and extend .NET-based systems supporting multiple banking entities Contribute to the integration of securities and core banking platforms Support and enhance a portfolio of ~17 applications across product control and risk management Work with an in-house development framework in a full-stack capacity Participate in scaling applications for cloud-based, containerized environments Collaborate closely with business stakeholders to deliver robust solutions Ensure high code quality through unit and integration testing Key Requirements: 5+ years of professional experience as a .NET / C# Developer Hands-on experience in the banking or investment banking sector (mandatory) Full-stack development experience (backend-focused, frontend included) Strong understanding and practical application of SOLID design principles Experience with document-based databases (e.g. MongoDB) Experience with event-driven / event-based messaging frameworks Solid knowledge of unit and integration testing Experience working end-to-end on applications (development, testing, support) Ability to work independently in a fast-paced, regulated environment Availability during UK business hours Nice to Have: Experience with cloud platforms and application migration to cloud Experience with container technologies (e.g. Docker, Kubernetes) Exposure to systems such as Murex or large in-house banking platforms Background in securities, risk, or product control systems Other Details: This role is 100% remote with candidates required to be located in Poland. The contract is on a B2B basis within the banking and investment banking industry.