Demo

Sr. .Net Engineer x4

Apex Systems
Portland, ME Full Time
POSTED ON 9/16/2025
AVAILABLE BEFORE 10/16/2025
Job#: 2086042

Job Description:

Job Title: Senior .NET Developer

Duration: Full time direct hire

Rate: Negotiable

Work Location: (multiple options)

  • Portland, ME
  • Boston, MA
  • Dallas, TX
  • Minneapolis, MN
  • Chicago, IL:

Project Overview:

Join a dynamic team working on a customer-facing platform for Corporate Payments. This platform includes user interfaces, APIs, webhooks, and data streams, and is undergoing a major transformation to enhance security and identity management.

Key Responsibilities:

  • Security Integration: Implement a new security framework using OAuth protocols and One WEX Identity (OWI). Experience with tools like Auth0 and modern authentication methods is essential.
  • Legacy System Modernization: Update existing SOAP services and .NET technologies to align with new security standards.
  • User Identity Management: Strategically separate and migrate identity data between service users and human users to support new ID structures.
  • Platform Migration: Support the migration of the EnCompass platform to OWI to ensure compliance and mitigate risk.
  • Infrastructure Support: Work within an AWS-hosted environment, with a focus on integration and security rather than infrastructure.

Required Skills:

  • 5–8 years of experience in .NET development
  • Strong understanding of OAuth or similar authentication protocols
  • Proven experience with APIs (SOAP preferred; REST acceptable)
  • Solid background in unit and integration testing
  • AWS experience is a plus

EEO Employer

Apex Systems is an equal opportunity employer. We do not discriminate or allow discrimination on the basis of race, color, religion, creed, sex (including pregnancy, childbirth, breastfeeding, or related medical conditions), age, sexual orientation, gender identity, national origin, ancestry, citizenship, genetic information, registered domestic partner status, marital status, disability, status as a crime victim, protected veteran status, political affiliation, union membership, or any other characteristic protected by law. Apex will consider qualified applicants with criminal histories in a manner consistent with the requirements of applicable law. If you have visited our website in search of information on employment opportunities or to apply for a position, and you require an accommodation in using our website for a search or application, please contact our Employee Services Department at [email protected] or 844-463-6178.

Apex Systems is a world-class IT services company that serves thousands of clients across the globe. When you join Apex, you become part of a team that values innovation, collaboration, and continuous learning. We offer quality career resources, training, certifications, development opportunities, and a comprehensive benefits package. Our commitment to excellence is reflected in many awards, including ClearlyRated's Best of Staffing® in Talent Satisfaction in the United States and Great Place to Work® in the United Kingdom and Mexico.

Apex Benefits Overview: Apex offers a range of supplemental benefits, including medical, dental, vision, life, disability, and other insurance plans that offer an optional layer of financial protection. We offer an ESPP (employee stock purchase program) and a 401K program which allows you to contribute typically within 30 days of starting, with a company match after 12 months of tenure. Apex also offers a HSA (Health Savings Account on the HDHP plan), a SupportLinc Employee Assistance Program (EAP) with up to 8 free counseling sessions, a corporate discount savings program and other discounts. In terms of professional development, Apex hosts an on-demand training program, provides access to certification prep and a library of technical and leadership courses/books/seminars once you have 6 months of tenure, and certification discounts and other perks to associations that include CompTIA and IIBA. Apex has a dedicated customer service team for our Consultants that can address questions around benefits and other resources, as well as a certified Career Coach. You can access a full list of our benefits, programs, support teams and resources within our ‘Welcome Packet’ as well, which an Apex team member can provide.

Apex Systems is a world-class IT services company that serves thousands of clients across the globe. When you join Apex, you become part of a team that values innovation, collaboration, and continuous learning. We offer quality career resources, training, certifications, development opportunities, and a comprehensive benefits package. Our commitment to excellence is reflected in many awards, including ClearlyRated's Best of Staffing® in Talent Satisfaction in the United States and Great Place to Work® in the United Kingdom and Mexico.

Apex Benefits Overview: Apex offers a range of supplemental benefits, including medical, dental, vision, life, disability, and other insurance plans that offer an optional layer of financial protection. We offer an ESPP (employee stock purchase program) and a 401K program which allows you to contribute typically within 30 days of starting, with a company match after 12 months of tenure. Apex also offers a HSA (Health Savings Account on the HDHP plan), a SupportLinc Employee Assistance Program (EAP) with up to 8 free counseling sessions, a corporate discount savings program and other discounts. In terms of professional development, Apex hosts an on-demand training program, provides access to certification prep and a library of technical and leadership courses/books/seminars once you have 6 months of tenure, and certification discounts and other perks to associations that include CompTIA and IIBA. Apex has a dedicated customer service team for our Consultants that can address questions around benefits and other resources, as well as a certified Career Coach. You can access a full list of our benefits, programs, support teams and resources within our ‘Welcome Packet’ as well, which an Apex team member can provide.

Apex Systems is part of the Commercial Segment of ASGN Incorporated.

NYSE: ASGN

4400 Cox Road

Suite 200

Glen Allen, Virginia 23060

Apex Systems is an equal opportunity employer. We do not discriminate or allow discrimination on the basis of race, color, religion, creed, sex (including pregnancy, childbirth, breastfeeding, or related medical conditions), age, sexual orientation, gender identity, national origin, ancestry, citizenship, genetic information, registered domestic partner status, marital status, disability, status as a crime victim, protected veteran status, political affiliation, union membership, or any other characteristic protected by law. Apex will consider qualified applicants with criminal histories in a manner consistent with the requirements of applicable law. If you have visited our website in search of information on employment opportunities or to apply for a position, and you require an accommodation in using our website for a search or application, please contact our Employee Services Department at [email protected] (Do not submit resumes or solicit consultants to this email address). UnitedHealthcare creates and publishes the Transparency in Coverage Machine-Readable Files on behalf of Apex Systems.

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