Summary: Seeking a hands-on Senior .NET Engineer to design, build, and deliver high-quality, scalable enterprise SaaS applications, taking full ownership of development and testing. Highlights: 1. Design and implement scalable enterprise SaaS applications 2. Hands-on role with full ownership of development and testing 3. Utilize AI development tools for enhanced productivity **Job Title:** Senior .NET Developer (Backend Developer) **Location:** Mexico Remote **Employment Type:** Full\-Time Permanent **Client Domain:** HRMS (Human Resource Management System) applications for public sector organizations 5\+ Years of Experience We're looking for a hands\-on Senior .NET Engineer to help design, build, and deliver high\-quality, scalable enterprise SaaS applications. This role is ideal for someone who enjoys solving complex problems, writing clean code, and taking full ownership of their work\-including testing and quality. What You'll Be Doing Break down large or complex problems into smaller parts, design clean solutions, and implement the core framework. Build and maintain RESTful APIs and backend services using C\#, .NET Core, Entity Framework, and Web API. Apply software architecture patterns like Domain\-Driven Design (DDD) and CQRS to build modular and scalable systems. Work directly with SQL Server\-designing databases, writing stored procedures, optimizing queries, and tuning performance. Use Entity Framework (EF Core or EF6\) for ORM and data access. Write clean, testable, and maintainable code with proper documentation. Take full ownership of testing your own code\-unit, integration, and performance testing\-as part of a Shift Left / No QA team setup. Collaborate with product managers and other teams to understand requirements and deliver customer\-focused features. Use AI development tools (required)\-including GitHub Copilot, Claude, or similar\-to assist with code generation, refactoring, documentation, and development speed.