Demo

Full Stack Developer

Apex Systems
Englewood, CO Full Time
POSTED ON 4/20/2026
AVAILABLE BEFORE 5/20/2026
Job#: 3027390

Job Description:

Position Overview

The Senior Full Stack Software Engineer plays a key role in designing, developing, and maintaining enterprise-grade applications using modern technologies and best practices. This role requires deep expertise in backend development with Java, complemented by hands-on experience in front-end technologies. The engineer will collaborate closely with cross-functional teams, contribute to architectural decisions, and ensure high-quality, scalable, and secure software solutions.

Key Responsibilities

  • Design, develop, test, debug, and document software solutions following the company’s established software development lifecycle.
  • Translate functional requirements and analysis documents into robust technical design specifications.
  • Review functional requirements, technical designs, and code to ensure quality, consistency, and alignment with architectural standards.
  • Build and maintain backend services with a strong emphasis on Java and related frameworks.
  • Contribute to front-end development using modern JavaScript frameworks and tools.
  • Develop and maintain RESTful APIs and microservices-based architectures.
  • Work with various database technologies, including SQL and NoSQL systems.
  • Participate in architecture discussions, design sessions, and code reviews.
  • Collaborate with other engineers, product managers, and stakeholders to deliver high-quality software.
  • Create and maintain operational, system-level, and technical documentation.
  • Support the adoption and integration of AI-driven tools and methodologies, including AI-assisted unit testing.
  • Troubleshoot complex issues across the full stack and provide production support as needed.

Required Qualifications

  • 10 years of professional software development experience.
  • Strong proficiency in Java and related backend frameworks (e.g., Spring).
  • Recent hands-on experience with front-end development using JavaScript and modern frameworks.
  • Experience with Node.js in production environments.
  • Demonstrated ability to work across the full stack, with approximately 80–85% backend and 15–20% frontend focus.
  • Strong understanding of REST APIs and microservices architecture.
  • Experience with relational and non-relational databases, such as SQL, MongoDB, AWS-hosted databases, and Oracle.
  • Familiarity with containerization and orchestration technologies such as Kubernetes.
  • Experience with distributed caching or messaging systems (e.g., Redis, Kafka, ActiveMQ).
  • Ability to write clean, maintainable, and testable code.
  • Strong problem-solving skills and the ability to work collaboratively in a team environment.

Preferred Qualifications

  • Experience with MongoDB Atlas or AWS DocumentDB.
  • Exposure to AI/ML tools or frameworks, especially for automated testing or code generation.
  • Experience working in cloud environments (AWS preferred).
  • Familiarity with CI/CD pipelines and DevOps practices.
  • Knowledge of event-driven architectures.

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.

Salary : $80 - $85

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