Sr. Front-End Software Developer

Location: 100% on-site in either Denver, CO or Sterling, VA.
Client: CACI
PV: Apex Systems
Rate: $85-110/hr W-2
Work Authorization: No H1, OPT
Duration: Contract to Hire
Interview Mode: Video
Job Description:


Candidates MUST have TS/SCI Clearance and ideally Poly

Vendors – we have an immediate opening for a Sr. Front-End Software Developer for CACI. 100% on-site in either Denver, CO or Sterling, VA. Candidates MUST have TS/SCI Clearance and ideally Poly. If candidate does not have Poly they will need to be a rock-star candidate AND they would have to have not found a TS/SCI CI Poly candidate. Focus on TS/SCI CI Poly first and foremost but if you find a strong TS/SCI candidate send to me (also we have other TS/SC cleared roles so might be able to use elsewhere).

When sending candidates please include conversion salary expectations with the submittal.


We are seeking an experienced Senior Front-End Software Developer who will be supporting the development of highly visible, mission-critical cloud-native applications that provide advanced Situational Awareness and Collaboration capabilities.
This role focuses on building modern, responsive, and data-rich user interfaces that consume real-time information from distributed backend systems. The successful candidate will have deep expertise in JavaScript and TypeScript development, experience building sophisticated front-end applications, and a strong understanding of how front-end systems interact with microservices, streaming platforms, and cloud-native architectures.

You will work closely with backend engineers, architects, and mission stakeholders to build intuitive applications capable of processing and displaying large volumes of information in near real-time. Success in this role requires a strong understanding of asynchronous programming, concurrency patterns, API integration, and modern front-end development practices.

We use Svelte as its primary front-end framework. Prior Svelte experience is highly desired but not required for candidates with strong modern JavaScript framework expertise and a willingness to learn.

Key Responsibilities

• Design, develop, and maintain modern cloud-native front-end applications using JavaScript, TypeScript, and contemporary web technologies.
• Build highly intuitive user experiences that support mission-critical situational awareness and collaboration workflows.
• Develop efficient client-side applications capable of handling large data sets, concurrent requests, and near real-time information updates.
• Integrate front-end applications with RESTful APIs, WebSocket services, and distributed backend systems.
• Collaborate closely with backend engineers to consume services and leverage event-driven architectures, including Kafka-based data streams.
• Implement performant asynchronous data loading strategies utilizing promises, concurrency patterns, and modern browser capabilities.
• Optimize application performance, responsiveness, and scalability across multiple operating environments.
• Participate in architecture discussions and contribute to technical design decisions.
• Conduct code reviews and promote software engineering best practices.
• Mentor junior developers and contribute to the overall growth of the engineering team.
• Participate in Agile ceremonies and continuous improvement initiatives.

Required Qualifications

• Minimum of 7 years of professional software development experience, with a strong focus on front-end engineering.
• Advanced proficiency in JavaScript and TypeScript.
• Experience developing and deploying applications within Linux-based environments.
• Strong experience building modern web applications and user interfaces.
• Experience consuming and integrating RESTful web services and APIs.
• Strong understanding of asynchronous programming concepts, including Promises, async/await patterns, concurrency, and parallel data processing.
• Experience building applications that support near real-time data delivery and dynamic user experiences.
• Understanding of distributed systems and how front-end applications interact with microservices architectures.
• Demonstrated ability to lead technical efforts and mentor junior engineers.
• Bachelor's degree in Computer Science, Software Engineering, or related field; or graduation from an accredited coding bootcamp with equivalent experience.
• Must possess or be willing to obtain a CompTIA Security+ certification.

Preferred Qualifications

• Experience with Svelte or other modern front-end frameworks.
• Experience developing applications utilizing WebSockets and real-time communication technologies.
• Familiarity with Kafka and event-driven architectures, including consuming and visualizing data originating from streaming platforms.
• Experience supporting highly concurrent applications with complex data-loading requirements.
• Experience with Kubernetes, Docker, and cloud-native deployment environments.
• Experience delivering mission-critical applications within government, defense, intelligence, or other secure environments.
• Experience designing front-end architectures for highly available and scalable systems.
• Security+ certification.

Clearance Level: TS/SCI with CI Polygraph

• Position requires eligibility to access classified information and secure government facilities in support of program requirements.
• Candidates selected for this position must be able to satisfy all government requirements for access to classified information associated with the program.
• Experience working in classified environments and supporting mission-sensitive programs is highly desired.
• Current TS/SCI eligibility and CI Polygraph are strongly preferred.