Senior .NET Developer (Fintech) à France

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior . NET Developer (Fintech) based in France. We are looking for a senior backend engineer to build and maintain reliable financial technology services supporting payment processing and business operations. In this role, you will develop scalable microservices and robust integrations for complex workflows such as reconciliation, payouts, settlements, and fee calculations. You will work with modern cloud infrastructure and database technologies to deliver secure, high-performance solutions. You will also leverage AI-powered development tools and agents to accelerate delivery while ensuring every implementation meets high engineering standards. Working within an international, fully remote team, you will contribute to technical decisions, maintain clear documentation, and share knowledge with fellow engineers. This is an opportunity to take ownership of critical fintech systems in a dynamic, product-driven environment. Accountabilities You will take responsibility for developing and improving backend services across payment processing and financial operations, ensuring reliability, scalability, and maintainability. Your main responsibilities will include: - Develop and maintain backend services supporting payment processing and back-office operations, including reconciliation, payouts, fee calculations, settlements, and B2B client dashboards. - Design and implement resilient integrations and asynchronous workflows using patterns such as idempotency, outbox/inbox, sagas, retries, and deduplication. - Build and optimize microservices to meet performance and reliability objectives, including p95/p99 latency targets and SLA/SLO requirements. - Implement monitoring, alerting, and operational practices to maintain service availability and quickly identify potential issues. - Use AI-powered development tools and agents throughout the software delivery process, from task definition to implementation. - Thoroughly review and validate AI-generated code, ensuring correctness, maintainability, security, and appropriate test coverage.

- Write clean, well-structured code and develop automated tests to support software quality and long-term maintainability. - Participate in code reviews, maintain up-to-date technical specifications, and share knowledge and best practices with the engineering team. - Take ownership of assigned deliverables, communicate openly about challenges, and proactively address defects or implementation issues. Requirements The ideal candidate is an experienced . NET developer with strong backend engineering skills, practical cloud experience, and the ability to deliver production-ready software using modern AI-assisted development workflows. The following qualifications are expected: - At least 5 years of commercial software development experience with C# and ASP. NET Core. - Proven experience designing and developing microservices architectures. - Hands-on experience with Microsoft Azure, Docker, and Azure Kubernetes Service (AKS). - Practical experience with Microsoft SQL Server, MongoDB, and Cosmos DB. - Demonstrated experience using AI-powered development tools or agents to deliver tasks from initial definition through to working implementation. - Ability to understand, validate, explain, and take responsibility for every line of code delivered, including AI-generated code. - Strong commitment to clean, maintainable code and automated testing. - A strong sense of ownership, accountability, and reliability when managing technical responsibilities. - Clear and open communication skills, particularly when addressing challenges, defects, or unexpected outcomes. Additional experience that would be advantageous: - Background in payment processing, financial technology, or banking systems.