Senior .NET Engineer: Enterprise API & Systems

Onemain; Salt Lake City (UT); On-site; USD 95,000 - 135,000; Full time

Job summary

OneMain Holdings, Inc. is seeking a seasoned .NET software engineer to contribute to the architecture and development of core systems such as loan origination and servicing platforms, and customer-facing applications.

You will work in a collaborative, Agile environment with DevOps practices, implement RESTful services, APIs, and integrations, and help modernize legacy systems while ensuring scalable, secure software across multi-tier architectures.

Qualifications

• 3-5+ years of experience developing enterprise-grade applications in .NET.
• Strong skills in T-SQL, C#, and the .NET Framework with experience in backend service design.
• Understanding of distributed systems and multi-tier application architectures.
• Hands-on experience with WPF/XAML, LINQ, MVVM, and WebAPI; exposure to React or Angular is a plus.
• Proficiency in RESTful API design, JSON, and XML integrations.
• Ability to explain technical concepts clearly across teams.
• Experience working in Agile environments with DevOps practices.
• Bachelor's degree in Computer Science, Engineering, or related field.
• Interest in mentoring peers and promoting modern development practices.

Responsibilities

• Contribute to the architecture and development of key systems including Loan Origination Systems, Loan Servicing Systems, and customer-facing applications (e.g., omfauto.com, foursight.com, rateworks.com).
• Ensure scalable, maintainable, and secure software design within assigned projects.
• Implement APIs, middleware services, and integrations with internal and external tools such as Twilio Flex.
• Collaborate with peers through code reviews, design discussions, and pairing sessions.
• Support automation and continuous integration strategies to improve development efficiency and reliability.
• Assist in technical initiatives to modernize legacy systems and improve scalability.
• Participate in troubleshooting and performance tuning to maintain system health.

Skills

3-5+ years experience

T-SQL & C#

Distributed systems

WPF/XAML

LINQ

MVVM

WebAPI

React/Angular

RESTful APIs

JSON

XML

Communication

Agile

DevOps

Mentoring

Education

Bachelor's degree in Computer Science, Engineering, or related field

Job description

OneMain Holdings, Inc. is seeking a seasoned .NET software engineer to contribute to the architecture and development of core systems such as loan origination and servicing platforms, and customer-facing applications.

You will work in a collaborative, Agile environment with DevOps practices, implement RESTful services, APIs, and integrations, and help modernize legacy systems while ensuring scalable, secure software across multi-tier architectures.