Senior .NET Architect: Modernize & Scale Large Systems

vTech Solution; Washington (District of Columbia); Hybrid; USD 150,000 - 190,000; Full time

Job summary

vTech Solution is seeking a highly experienced Principal C#/.NET Engineer to modernize a large legacy mainframe system into a clean, scalable .NET application. You will drive code refactoring, define data architecture with EF Core, optimize APIs and batch processing, and ensure high-quality delivery in a mission-critical environment.

The role involves mentoring the team, establishing development standards, and ensuring robust testing, CI/CD, and secure coding practices across on-site and hybrid

Qualifications

• 10+ years of experience in C# and .NET Core/.NET 6/7/8/10 development.
• Strong expertise in Entity Framework Core, LINQ, and asynchronous programming (async/await).
• Experience with RESTful APIs, PostgreSQL, and software architecture principles.
• Knowledge of Angular, TypeScript, and Node.js.
• Familiarity with testing frameworks, Git, SonarQube, Docker, CI/CD pipelines, and AWS cloud services.

Responsibilities

• Refactor legacy-converted code into maintainable C#/.NET solutions.
• Lead design, optimization, and migrations using Entity Framework Core.
• Build and enhance ASP.NET Core Web APIs and service layers.
• Improve performance, scalability, and overall code quality.
• Define development standards and mentor engineering team members.
• Ensure strong testing, CI/CD, and secure coding practices.

Skills

C#/.NET

Entity Framework Core

LINQ

Async/Await

RESTful APIs

PostgreSQL

Angular

TypeScript

Node.js

Docker

CI/CD

AWS

Software Architecture

Git

SonarQube

Tools

Docker

Git

SonarQube

CI/CD pipelines

AWS

Job description

vTech Solution is seeking a highly experienced Principal C#/.NET Engineer to modernize a large legacy mainframe system into a clean, scalable .NET application. You will drive code refactoring, define data architecture with EF Core, optimize APIs and batch processing, and ensure high-quality delivery in a mission-critical environment.

The role involves mentoring the team, establishing development standards, and ensuring robust testing, CI/CD, and secure coding practices across on-site and hybrid