Senior .NET Developer - AWS Migration

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 C# and 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 C# experience 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.

• Flexible compensation package including private health insurance, meal vouchers, childcare vouchers, and transportation benefits.

• Free English classes to help you improve or reinforce your language skills.

• Access to an extensive employee benefits platform where you can purchase products and services from various sectors at discounted rates, including flights, hotels, fashion, technology, home goods, and more.

About Izertis

At Izertis, we drive the digital transformation of companies, organizations, and individuals through tailored, innovative technology solutions that deliver real impact.

Founded in 1996 and now approaching 30 years of history, Izertis is listed on the Spanish Stock Exchange (BME Continuous Market) and has established itself as one of the 1,000 fastest-growing companies in Europe.

Today, we are more than 2,300 professionals working from offices across Europe, the Americas, and Africa, with a presence in over 50 countries. We deliver services and projects through a broad portfolio of solutions, including:

• Software Engineering

• Consultancy & Governance

• Cloud & Infrastructure

• Cybersecurity

• AI, Data & Emerging Technologies

• Customer Experience (CX) & Business Solutions

• Other transformation-enabling technologies

Would you like to be part of our team? If so, don't hesitate to apply so that our Talent team can get to know you.

Also, be sure to check the careers section of our website for other opportunities that may be of interest to you:

https://www.izertis.com/es/talento