Senior Full-Stack .NET Developer
Remote in Brazil, & 2 others
.NET& 12 others
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We are looking for a Senior Full-Stack .NET Developer to remediate security vulnerabilities, support legacy applications, and modernize services across .NET Framework and .NET 6/8+. You will work across backend, data, and frontend while partnering on secure delivery.
Responsibilities
- Investigate and remediate application security vulnerabilities across OWASP Top 10 and automated SAST/DAST findings
- Harden applications against SQL injection, XSS, and dependency-related risks
- Maintain and modernize legacy .NET Framework applications including ASP.NET Web Forms, ASP.NET MVC, WCF, and ASMX
- Build and enhance ASP.NET Core Web APIs and modern .NET services using clean architecture practices
- Implement secure data access with Microsoft SQL Server and ADO.NET
- Develop and refine frontend features using JavaScript and existing UI patterns
- Collaborate with DevOps to support secure CI/CD pipelines and production deployments
- Troubleshoot production issues and deliver timely fixes with minimal risk
- Review code changes for security, maintainability, and backward compatibility
- Document remediation decisions and modernization steps for future maintenance
Requirements
- 3+ years of full-stack .NET development experience
- Strong leadership and ownership skills to drive remediation and modernization work
- Daily availability aligned to 5:00 PM CT (Central Time)
- C# and .NET Framework expertise including ASP.NET MVC and Web Forms
- Strong application security knowledge covering OWASP Top 10 vulnerabilities
- REST API development skills with ASP.NET Core and modern .NET (6/8+)
- Microsoft SQL Server and ADO.NET skills for secure data access
- WCF experience supporting and maintaining legacy services
- JavaScript skills for frontend enhancements and integrations
- Strong troubleshooting skills to diagnose issues in large legacy codebases
- Clear communication skills to collaborate across engineering and DevOps
- Upper-Intermediate English skills (B2+)
Nice to have
- OAuth2 knowledge for secure authorization flows
- OpenID Connect knowledge for modern identity integration
- Octopus Deploy experience supporting deployments
- Strong HTML skills for maintaining legacy views
- Strong CSS skills for UI fixes and incremental improvements
