Senior .NET Developer - AWS Migration Published 19 of October At Izertis we are seeking an experienced Senior .NET Developer. As a Senior .NET Developer - AWS Migration, you will support, modernize, and migrate business-critical .NET applications from on-premises infrastructure to AWS. The role requires strong hands-on C#/.NET engineering combined with deep AWS architecture and migration expertise. You will interact frequently with software developers, testers, product managers, infrastructure, security, operations, and other stakeholders to ensure a controlled migration and a high-quality production platform. Key Responsibilities

- Analyze existing .NET applications, IIS/Windows hosting, services, scheduled jobs, integrations, databases, certificates, file shares, and infrastructure dependencies to define migration plans.
- Design and implement new modules, APIs, services, and modernization changes using Cand current .NET technologies.
- Modernize legacy .NET Framework workloads where practical, including migration toward .NET 6/8+, ASP.NET Core, Linux/container hosting, or AWS managed services.
- Replatform or refactor applications for EC2, ECS/Fargate, EKS, Lambda, API Gateway, or other AWS services based on workload requirements.
- Migrate Windows/web services, background processes, configuration, secrets, file processing, database connectivity, and integrations to secure AWS patterns.
- Design and support relational database migration, connection resiliency, ORM/data access patterns, and application compatibility for cloud-hosted databases.
- Implement automated testing, CI/CD, infrastructure automation, cloud observability, performance tuning, and production support.
- Develop detailed cutover, rollback,



validation, and stabilization plans and participate hands-on in migration events.
- Work with developers and project management to understand requirements, estimate work, manage technical dependencies, and deliver production-quality software.

Required Skills & Experience
- Bachelor's Degree in Computer Science, Engineering, or related field, or equivalent professional experience.
- 8+ years of professional software development experience, including 5+ years of strong C#/.NET development experience in enterprise production systems.
- Strong Cexperience with .NET 6/8+ and ASP.NET Core; solid working knowledge of .NET Framework applications and legacy modernization considerations.
- Strong experience with REST APIs, Web APIs, dependency injection, asynchronous programming, background services, serialization, authentication/authorization, and automated testing.
- Strong knowledge of OOP, SOLID principles, design patterns, service-oriented/microservice architectures, and distributedsystem troubleshooting.
- Strong experience with SQL Server and/or Oracle; practical experience with Entity Framework/EF Core or equivalent dataaccess approaches.
- Experience supporting IIS-hosted applications, Windows services, and web services, with the ability to migrate or redesign them for AWS-hosted environments.




- Hands-on experience with Git-based source control, code reviews, build automation, and CI/CD pipelines.
- Extensive and deep AWS experience meeting all requirements in Section 4, including direct on-premises-to-AWS migration delivery.
- Strong written and verbal communication skills, with a proven record of producing estimates, technical designs, migration runbooks, and implementation documentation.
- Ability to work independently or as part of a cross-functional team and deliver production-quality software within tight schedules.

Nice-to-Have Skills
- Experience migrating .NET Framework/Windows workloads to .NET 6/8+, Linux containers, ECS/Fargate, or EKS.
- Experience with AWS Lambda for .NET, API Gateway, SQS/SNS, EventBridge, Step Functions, or serverless integration patterns.
- Experience with AWS DMS/SCT, SQL Server/Oracle migrations to RDS/Aurora, and database cutover strategies.
- Experience with JavaScript/TypeScript and modern web front-end integration where applicable.
- Prior experience delivering technology solutions within Capital Markets or Investment Banking is strongly preferred, particularly experience supporting trading, securities, Equities, Fixed Income, or front-to-back processing environments.
- Experience with Jira, Confluence, GitHub, and approved AI-assisted software development tools.

What can we offer you?

- Permanent contract from day one.
- 22 working days of annual leave, your birthday off, plus December 24th and 31st as additional days off.
- Versátil compensation package including private health insurance, meal vouchers, childcare vouchers, and trans

📌 Senior .NET Developer (Madrid)
🏢 Izertis
📍 Madrid