Senior Software Engineer (.NET/C#/Azure)

Ontrac Solutions LLC.; Chicago (IL); Remote; USD 120,000 - 180,000; Full time

Job summary

OnTrac is seeking a Senior Software Engineer (.NET / C# / Azure) for a remote contractor program supporting a large wholesale digital-marketplace customer. You will write production C# on .NET Core, work with Azure and Azure DevOps, and collaborate across teams to translate business requirements into scalable software.

The role involves implementing core platform features, collaborating with product managers, and delivering high-quality code within an agile environment.

Qualifications

• Bachelor's degree in Computer Science, Software Engineering, or a related field.
• 7+ years of C# development experience with strong OO principles.
• Extensive .NET Core and C# experience.
• Experience with React and modern front-end tooling.
• Proficiency with Azure cloud services and CI/CD pipelines in Azure DevOps.
• Experience designing RESTful APIs and with ORM (Entity Framework).

Responsibilities

• Implement core features for the new platform across inventory, transactions and customer management.
• Collaborate with multiple teams and product managers to translate requirements into solutions.
• Develop high-quality, maintainable C# code in an agile environment.
• Design data models and database interactions; ensure performance and reliability.
• Integrate new system with existing platforms and third parties.
• Perform code reviews and provide constructive feedback.
• Troubleshoot issues and contribute to technical documentation and best practices.

Skills

C# development

.NET Core

Azure

RESTful APIs

SQL Server

PostgreSQL

NoSQL

Entity Framework

React

Azure DevOps

Object‑oriented programming

API design

GraphQL

Kafka

Next.js

Education

Bachelor's degree in Computer Science

Tools

Azure DevOps

GraphQL

Kafka

Job description

OVERVIEW

OnTrac is seeking a Senior Software Engineer (.NET / C# / Azure) to join a contractor program supporting a large wholesale digital-marketplace customer. The customer is rebuilding its digital auction platform and decoupling it from a legacy auction management system, standing up a new, independent, modern auction backend purpose-built for a digital-first marketplace. Phase 1 delivers the core platform: inventory management, financial transactions, and customer management. The initiative is broad in scope and spans four or more teams. This role is ideal for a hands‑on senior engineer who writes production C# on .NET Core, is comfortable on Azure and Azure DevOps, and can collaborate across teams to turn business requirements into maintainable, scalable software.

ENGAGEMENT

• Expected start: ASAP
• Location: United States, fully remote

RESPONSIBILITIES

• Implement core features for the new platform, which could include inventory management, financial transactions, and customer management
• Collaborate closely with team members, other teams, and product managers to translate business requirements into technical solutions
• Develop high-quality, maintainable, and efficient C# code within an agile development environment
• Design and implement efficient data models and database interactions
• Integrate the new system with existing platforms and third-party systems
• Conduct code reviews and provide constructive feedback to peers
• Troubleshoot and debug issues, ensuring optimal performance and reliability
• Contribute to technical documentation and best practices

REQUIRED QUALIFICATIONS

• Bachelor's degree in Computer Science, Software Engineering, or a related field
• 7+ years of experience in C# development, with a strong understanding of object‑oriented programming principles
• Extensive experience with .NET Core and C#
• Familiarity with front-end development using modern frameworks, specifically React
• Experience with the Microsoft Azure cloud platform, including core services and infrastructure
• Experience creating and optimizing CI/CD pipelines, specifically within Azure DevOps
• Understanding of software architecture principles and best practices, with proficiency in applying design patterns to solve technical challenges
• Proficiency in designing and developing RESTful APIs
• Solid understanding of database systems and storage (e.g., SQL Server, PostgreSQL, NoSQL) and ORM frameworks (e.g., Entity Framework)
• Demonstrated ability to write clean, testable, and efficient code
• Strong problem-solving skills and attention to detail
• Excellent communication and collaboration skills
• Experience with agentic workflows
• Comfortable working with AI and AI‑assisted development tools

USEFUL QUALIFICATIONS

• Contemporary JavaScript / TypeScript (ES2015+), React Hooks, Next.js, Nx
• Experience with a message queue such as Kafka or RabbitMQ
• Experience writing GraphQL‑interfaced services
• Experience working with authentication and authorization