Sr Software Engineer Java Jobs in Denver, CO (NOW HIRING)

About Four Sea Group, Inc.

Four Sea Group is a 100% employee-owned technical mission support company based in Denver, Colorado. Founded by an aerospace industry veteran and PhD astrophysicist, we support complex defense, space, software, systems, and mission-focused programs for government and industry partners. What sets FSG apart is the caliber of our people and the way we operate: we are a reputation-driven team of highly skilled engineers and technical experts who are brought in for their depth, judgment, and ability to solve difficult problems. As an employee-owned company, we have built our compensation, benefits, and culture around a simple idea: when the company succeeds, that value should go back to the people doing the work.

About the role

Four Sea Group is seeking a Senior Software Engineer specializing in Java development to design, develop, modernize, and maintain complex software applications supporting secure customer missions.

This role contributes to Four Sea Group’s ability to deliver reliable, scalable, and maintainable software in high-consequence environments. The engineer will own significant application components and services, translate complex requirements into effective technical solutions, and help reduce program risk through sound design, disciplined testing, performance improvement, and resolution of difficult production and integration issues.

The ideal candidate brings deep Java development experience, strong object-oriented design capability, and practical expertise building enterprise applications, APIs, microservices, and database-integrated solutions. This role also requires the ability to collaborate across software development, quality assurance, integration, and DevOps teams while providing technical guidance within the engineer’s area of expertise.

Required Qualifications

• Bachelor’s degree in Computer Science, Software Engineering, Computer Engineering, or a related technical field, or equivalent practical experience.
• Eight or more years of relevant software engineering experience, including substantial professional Java development experience.
• Active Top Secret clearance needed to start with the ability to obtain and maintain a TS/SCI with CI Poly
• Advanced proficiency developing enterprise applications using Java SE or Java EE.
• Experience with Java frameworks such as Spring Boot, Hibernate, or comparable technologies.
• Strong understanding of object-oriented design, established design patterns, and SOLID principles.
• Experience designing and developing RESTful APIs, microservices, or service-oriented applications.
• Experience integrating software with SQL, NoSQL, or comparable database technologies.
• Experience developing and maintaining unit tests using JUnit, TestNG, or comparable frameworks.
• Experience with build tools, Git-based version control, code reviews, and collaborative software-development workflows.
• Experience troubleshooting production software, resolving performance concerns, and improving or refactoring legacy components.
• Ability to independently own a major application component, service, or technical area and determine appropriate implementation approaches.
• Ability to communicate technical decisions, risks, dependencies, and tradeoffs to engineering and program stakeholders.
• Experience working within an Agile software-development environment.
• Strong written and verbal communication skills.
• All candidates must work in-person in Aurora (no virtual)

Preferred Qualifications

• Experience developing software for U.S. government, defense, intelligence, or other secure mission environments.
• Experience with automated testing pipelines, continuous integration, and continuous deployment.
• Experience with Docker or another containerization technology.
• Experience deploying or supporting applications within AWS, Azure, Google Cloud, or another cloud platform.
• Experience modernizing enterprise or mission-critical Java applications.
• Experience providing technical guidance or mentoring to other software engineers.
• Experience working across software development, integration, test, and DevOps teams.
• Experience with SAFe or another scaled Agile framework.

Salary: The salary range for this role is $152,000.00 – $262,000.00 per year. The salary range provided is a good faith estimate representative of all experience levels. Four Sea Group, Inc. considers several factors when extending an offer, including but not limited to, the role, function and associated responsibilities, a candidate’s work experience, location, education/training, key skills, and market conditions.

Application Deadline: This position is expected to remain open through September 30, 2026 . The company may adjust this deadline based on business needs and will update the posting as appropriate.

Benefits: FSG is 100% ESOP-owned, which means our employees share directly in the company’s growth. We offer competitive compensation, a strong employer-funded retirement plan, generous PTO and flexible time-off options, comprehensive health, dental, vision, life, short-term disability, and long-term disability benefits, plus a generous medical stipend that gives employees more choice and flexibility. Our model is intentionally built to keep more value with employees through salary, retirement, benefits, and ownership. You will work alongside experienced engineers and technical leaders on meaningful defense, space, software, systems, and mission support work, with room to grow as a technical expert, mentor, program contributor, or future leader.
EEO Statement: Four Sea Group is an equal opportunity employer and considers qualified applicants for employment without regard to race, color, sex, sexual orientation, gender identity or expression, religion, national origin, marital or familial status, age, disability, veteran status, militaryserviceor application for military service.