Senior Software Engineer (.NET / C# / RESTful APIs)

This position is open exclusively to candidates who are currently residing in Mexico. Before applying, we encourage you to review our open positions and make sure the location requirements match your current location. Candidates who are not currently based in Mexico will not be contacted for this opportunity.

Nexaminds is looking for a Senior Software Engineer to design, develop, and maintain scalable enterprise applications and backend services using C#, .NET Core, SQL Server, and Entity Framework. The ideal candidate has strong hands-on experience building RESTful APIs following API-First design principles, with a focus on performance, scalability, maintainability, and code quality. This role combines backend development with technical collaboration, contributing to architectural decisions, engineering best practices, and the development of reliable solutions across distributed systems.

Qualifications we are looking for:

5–8 years of professional experience in software development using C# and .NET Core.

Strong hands-on experience designing, developing, and maintaining RESTful APIs following API-First design principles.

Strong proficiency in SQL Server, including database schema design, stored procedures, query optimization, and performance tuning.

Hands-on experience with Entity Framework / Entity Framework Core (EF Core).

Solid understanding of object-oriented programming (OOP), design patterns, and SOLID principles.

Experience with asynchronous programming, dependency injection, and unit testing frameworks.

Experience with Git, CI/CD pipelines, and Agile development methodologies.

Strong understanding of backend architecture, service integration, and scalable application design.

Strong analytical, troubleshooting, and problem-solving skills.

Excellent communication and collaboration skills.

Nice to have:

Experience with Microsoft Azure or AWS cloud services.

Familiarity with microservices architecture and containerization technologies such as Docker or Kubernetes.

Experience with message queues, caching mechanisms, or distributed systems.

Knowledge of Swagger / OpenAPI, API documentation, and API versioning.

Basic understanding of front-end technologies such as React, Angular, or Vue.

Job Duties:

Design, develop, and maintain RESTful APIs and backend services using C# and .NET Core.

Apply API-First design principles to build scalable, maintainable, and reusable services.

Define and maintain API specifications to ensure consistency, discoverability, and integration across applications.

Develop and optimize data access layers using Entity Framework Core and SQL Server.

Collaborate with Product, Front-End, QA, and Engineering teams to translate business requirements into reliable technical solutions.

Apply software engineering best practices, including clean code, design patterns, automated testing, and version control.

Contribute to CI/CD processes and continuous improvement of development workflows.

Troubleshoot and resolve complex application performance, scalability, and integration issues.

Conduct code reviews and provide technical guidance and mentorship to other developers.

Participate in architectural discussions involving backend services, API governance, and system integration.

Ensure applications meet quality, performance, security, and maintainability standards.