Principal Systems Engineer (API Gateway) - TS/SCI w CI Poly

Modern Government Solutions

$120K — $150K *
Aerospace & Defense
15+ years of experience
Job Overview by Ladders

Qualifications

  • Active DoD TS/SCI clearance with CI Polygraph is mandatory.
  • Must have Security+ CE certification per DoD 8140 requirements.
  • Bachelor's degree in a relevant field (Engineering, Computer Science, IT, etc.).
  • 16+ years of experience in enterprise systems and cloud architectures.
  • 5+ years of experience with API gateway technologies in cloud environments.
  • Proficient in designing secure APIs using REST, GraphQL, and related technologies.
  • Experience with programming languages such as Java, Python, C#, etc.

Responsibilities

  • Design and sustain enterprise API gateway solutions for secure integrations.
  • Architect cloud-based integrations using advanced API technologies.
  • Support Windows-based and cloud-hosted platforms in secure environments.
  • Troubleshoot and resolve complex integration issues across systems.
  • Develop and execute system testing and performance assessments.
  • Collaborate with stakeholders in a Scaled Agile Framework setting.
  • Evaluate and recommend new technologies for improved API and integration capabilities.

Benefits

  • Onsite work environment in Sterling, VA.
  • Opportunity to work on mission-critical national security projects.
  • Engagement with modern technologies such as cloud services and APIs.
  • Collaboration with a diverse team of experts across multiple disciplines.
Full Job Description
TITLE: Principal Systems Engineer (API Gateway)

LOCATION: Sterling, VA

CLEARANCE REQUIRED: Active TS/SCI with CI Poly

EMPLOYMENT TYPE: Full-time, Onsite

POSITION SUMMARY

Modern Government Solutions (MGS) is seeking a Principal Systems Engineer to architect, integrate, and secure mission-critical API ecosystems supporting next-generation national security capabilities. In this role, you will lead the design and implementation of API gateway solutions, cloud-native integrations, and enterprise service architectures that enable secure data exchange across complex environments. Working alongside software engineers, cloud architects, cybersecurity professionals, and mission stakeholders, you will help modernize critical systems through scalable APIs, automation, and cloud technologies. The ideal candidate brings deep expertise in API platforms, cloud architecture, systems integration, and troubleshooting complex enterprise environments while maintaining the engineering rigor required to support high-impact mission operations.

RESPONSIBILITIES (not limited to):
  • Design, implement, and sustain enterprise API gateway solutions and service architectures supporting secure system integration across mission environments.
  • Architect and support cloud-based integrations utilizing APIs, message queues, streaming platforms, ETL pipelines, and related technologies.
  • Support Windows-based platforms, COTS applications, and cloud-hosted systems within secure enterprise environments.
  • Troubleshoot complex application, infrastructure, and integration issues, performing root cause analysis and implementing corrective actions.
  • Develop and execute system testing, validation, and performance assessment activities to ensure operational readiness and reliability.
  • Collaborate with engineering, cybersecurity, infrastructure, and mission stakeholders to implement technical solutions and architectural improvements in a Scaled Agile Framework environment.
  • Participate in Program Increment and Sprint planning, to include t-shirt sizing, story point estimation, and dependency mapping.
  • Evaluate emerging technologies and recommend enhancements to API platforms, cloud architectures and infrastructure configurations, and enterprise integration capabilities.
  • Create and maintain technical documentation, architecture artifacts, implementation guides, and operational procedures.
  • Provide technical leadership and engineering guidance across API platform, cloud, and integration initiatives.
  • Ability to remain in a stationary position for extended periods while working at a computer workstation.
  • Ability to communicate effectively with customers, team members, and stakeholders in both written and verbal formats.


REQUIRED SKILLS AND QUALIFICATIONS
  • Must possess an active DoD TS/SCI security clearance with CI Polygraph.
  • Must meet DoD 8140 requirements, including Security+ CE certification.
  • Bachelor's degree in Systems Engineering, Computer Science, Computer Engineering, Software Engineering, Information Technology, Electrical Engineering, Mathematics, Physics, or a related field.
  • 16+ years of experience designing, integrating, and supporting enterprise systems, cloud architectures, and API-driven solutions within complex mission environments.
  • 5+ years of experience implementing and administering API gateway technologies in cloud-based architectures;
  • Experience designing secure APIs and enterprise integration solutions utilizing REST, GraphQL, event-driven architectures, message queues, streaming platforms, or ETL pipelines.
  • Experience supporting Windows-based platforms, COTS applications, and cloud environments utilizing AWS or Azure.
  • Experience developing software, automation, or integration solutions using Java, Python, C#, or similar programming languages, with demonstrated expertise in testing, validation, troubleshooting, root-cause analysis, and technical documentation.
  • This position requires regular onsite attendance at our Sterling, VA facility. Candidates must be able to reliably commute to the facility each workday and, when operational needs require, report to the facility within 60 minutes.


DESIRED SKILLS AND QUALIFICATIONS
  • Experience supporting Broadcom API Gateway, MuleSoft, Apigee, or similar API management platforms.
  • Experience designing and implementing service mesh architectures utilizing Istio, Linkerd, or similar technologies.
  • Experience supporting Model-Based Systems Engineering (MBSE) environments and tools.
  • Experience optimizing cloud-hosted solutions and supporting Google Cloud Platform (GCP), Oracle Cloud Infrastructure (OCI), IBM Cloud, or similar technologies.
  • Experience implementing ServiceNow integrations and supporting customer security requirements within classified environments.
  • Experience supporting virtualization technologies, application streaming, cloud-native architectures, and enterprise integration platforms.


*Applicants selected will be United States citizens and may be subject to a government security investigation for access to classified information.*

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