Full Description

Job#: 3017686

Job Description

Software Design Engineer 3

Start Date: 01/20/2026

End Date: 06/30/2026

Duration: Approx. 5 months

Chance for Extension: Yes

Location: Onsite – Redmond, WA

Openings: 1

Pay Rate Range: $60–$65/hr

Top 3 Must-Have Skills

C/C++ development: 5+ years

Operating systems knowledge (Windows): 3+ years

Networking protocols (IPSec, VPN technologies, QUIC): 2+ years

Role Overview

The Software Design Engineer will design, develop, implement, test, and maintain business and computer applications software or specialized utility programs, including client/server applications, as well as major enhancements to existing systems.

Typical Responsibilities

Troubleshoot, triage, and resolve failures in test pipelines across multiple projects. Modify and enhance test automation for network protocols and network security. Perform periodic manual tests for VPN, IPSec connection security tunnels, and Linux subsystems.

Ideal Background

Strong experience in C/C++ systems-level development. Familiarity with networking protocols such as IPSec, TCP, and QUIC. Comfortable with VPN technologies and software-defined networking. Expertise in PowerShell and YAML scripting. Experience working in both Windows and Linux environments. Skilled in debugging tools such as Wireshark, gdb, tcpdump, and system-level instrumentation.

Key Projects

Fine-tune and improve complex software implementation projects. Gather and analyze system requirements, document specifications, and develop solutions. Customize system software to meet client requirements. Prepare detailed design and test documentation. Implement new or modify existing programs and author automated tests. Perform post-implementation validation and resolve bugs.

Candidate Requirements

Preferred Strengths

Ability to write clean, maintainable systems-level code in C/C++. Strong debugging skills for legacy software using instrumentation and tracing tools. Experience analyzing WPP/ETW traces for complex system issues. Skilled in developing and enhancing automated test suites. Familiarity with VPN, IPSec-based security, and SDN technologies.

Qualifications

Bachelor’s degree in Computer Science, Computer Engineering, or related field. 5+ years of experience in software design and development. Strong foundation in data structures, algorithms, and software design principles. Experience with large-scale systems software development. Proficiency in troubleshooting and unit testing for both new and legacy systems. Sufficient proficiency in reading and writing code.

Required Technical Skills

Systems-level programming in C and C++. Operating systems knowledge (Windows and Linux).

Debugging tools: Windows Debugger, Wireshark, gdb, tcpdump. Experience with WPP/ETW trace analysis.

Networking protocols: IPSec, TCP, QUIC. VPN and SDN technologies. PowerShell and YAML scripting.

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 uses a virtual recruiter as part of the application process. Click here for more details.

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 uses a virtual recruiter as part of the application process. Click here for more details.

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 Benefits Department at [email protected] or 804-523-8228. (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.