Lead .Net Full Stack Developer

eSolutionsFirst, LLC; McLean (VA); On-site; USD 120,000 - 180,000; Full time

Job summary

eSolutionsFirst, LLC is seeking a senior software engineer in McLean, VA with 7+ years of experience to lead full-stack development across C#/.NET, React/TypeScript, and ERP integrations. The role emphasizes real-time systems, API contract-first design, and AI-assisted development workflows in production.

The candidate will implement scalable web applications, ensure security, and drive observability with modern telemetry.

Qualifications

• 7+ years of software development experience.
• Strong coding experience in C# / .NET, Unit testing, REST API design.
• Strong React / TypeScript / Next.js App Router, RTK Query, Tailwind CSS.
• Experience integrating with ERP systems (Dynamics NAV / Business Central strongly preferred).
• Proven experience designing real-time systems (SignalR, WebSockets, or equivalent).
• OpenAPI/Swagger specification authoring and API contract-first development.
• Hands-on experience with Claude Code, GitHub Copilot, or equivalent AI coding assistants in production development workflows
• Demonstrated ability to prompt LLMs effectively using structured specifications and to critically evaluate generated output
• Familiarity with AI-assisted test generation and automated code review tooling
• Track record delivering complex, multi-module web applications end-to-end
• Experience with message-driven integration patterns (Azure Service Bus, event-driven architecture, dead-letter handling)
• Security-conscious mindset: OWASP Top 10 familiarity, managed identity patterns, Azure Key Vault
• Observability and monitoring: Application Insights instrumentation, custom metrics, alerting design

Responsibilities

• Deliver complex, multi-module web applications end-to-end
• Implement message-driven integration patterns (Azure Service Bus, event-driven architecture)
• Maintain security by following OWASP Top 10 and using managed identities/Azure Key Vault
• Design observability with Application Insights, custom metrics and alerts

Skills

C# / .NET

Unit testing

REST API design

React

TypeScript

Next.js

App Router

RTK Query

Tailwind CSS

ERP integration

Dynamics NAV/BC

Real-time systems

SignalR

WebSockets

OpenAPI/Swagger

API contract-first

Tools

Claude Code

GitHub Copilot

Prompting LLMs

AI-assisted test generation

Automated code review tooling

Job description

Job Summary

7+ years of software development experience.

• Strong coding experience in any of these languages (C# and .Net), Unit testing, REST API design
• Strong React / TypeScript / Next.js 15 App Router, RTK Query, Tailwind CSS, component library patterns
• Experience integrating with ERP systems (Microsoft Dynamics NAV / Business Central strongly preferred)
• Proven experience designing real-time systems (SignalR, WebSockets, or equivalent)
• OpenAPI/Swagger specification authoring and API contract-first development

AI & Tooling

• Hands-on experience with Claude Code, GitHub Copilot, or equivalent AI coding assistants in production development workflows
• Demonstrated ability to prompt LLMs effectively using structured specifications and to critically evaluate generated output
• Familiarity with AI-assisted test generation and automated code review tooling

Architecture & Process

• Track record delivering complex, multi-module web applications end-to-end
• Experience with message-driven integration patterns (Azure Service Bus, event-driven architecture, dead-letter handling)
• Security-conscious mindset: OWASP Top 10 familiarity, managed identity patterns, Azure Key Vault
• Observability and monitoring: Application Insights instrumentation, custom metrics, alerting design