Senior Software Engineer (SSE) with Security Clearance

Endurion; Tampa (FL); On-site; USD 120,000 - 170,000; Full time

Job summary

Endurion is seeking a Senior Software Engineer to design, develop, modernize, and sustain enterprise applications supporting SOF, intelligence, and mission-critical operations in Tampa. You will migrate legacy .NET to modern platforms, build responsive web apps with Vue.js/Nuxt, and implement secure, scalable REST APIs and data-processing solutions across complex environments.

The role emphasizes DevSecOps practices, RMF/NIST controls, Azure DevOps, and modern architectural patterns.

Qualifications

• Bachelor’s degree in a technical field or 4+ years of relevant software engineering experience.
• Experience designing, developing, and sustaining enterprise software applications.
• Experience with REST APIs, web apps, and backend services.
• Experience with SDLC, modern practices, and secure coding.

Responsibilities

• Architect, build, modernize, and sustain enterprise applications including REST APIs and data-processing solutions.
• Migrate legacy .NET Framework to modern .NET platforms.
• Develop responsive web front ends using Vue.js/Nuxt.
• Apply SDLC, DDD, and TDD practices across projects.
• Ensure cybersecurity controls per NIST 800-53, RMF, and DoD STIGs.

Skills

Senior-level software engineering

REST APIs

Vue.js/Nuxt

C#/.NET

DevSecOps

Azure DevOps

SQL Server/Oracle

SDLC/TDD/DDD

Education

Bachelor’s degree in Computer Science or related field

Tools

Azure DevOps

SQL Server

Oracle

Git

Job description

Job Title: Senior Software Engineer
Location: Tampa, FL
Security Clearance: TS/SCI; must be able to obtain an interim Secret Clearance as soon as possible
Position Overview Endurion is seeking a skilled Senior Software Engineer to design, develop, modernize, and sustain enterprise software applications supporting Special Operations Forces (SOF), intelligence, and mission-critical operations. The ideal candidate will have strong full-stack software engineering experience and the ability to develop secure, scalable applications, REST APIs, background services, and data-processing solutions across complex enterprise environments. This role will contribute to the modernization of existing applications, including migration from legacy .NET Framework 4.7.x to modern .NET platforms, while developing responsive web applications using modern frameworks such as Vue.js and Nuxt. The Senior Software Engineer will work across the full software development lifecycle, applying sound engineering practices, cybersecurity principles, automated testing, DevSecOps methodologies, and modern architectural patterns. The position offers an opportunity to develop innovative technical solutions supporting SOF missions, multiple military branches and government agencies, and mission-critical identity and intelligence applications with global impact.

Key Responsibilities

• Architect, build, modernize, and sustain enterprise applications, REST APIs, background services, and data-processing solutions using monolithic and service-based architectures.
• Modernize legacy applications from .NET Framework 4.7.x to current .NET platforms, applying appropriate modernization strategies and minimizing operational risk.
• Develop responsive web front ends using Vue.js, Nuxt, and related modern web frameworks.
• Apply software engineering practices throughout the Software Development Lifecycle (SDLC), including Object-Oriented Design, Domain-Driven Design (DDD), and Test-Driven Development (TDD).
• Apply modern architectural and modernization patterns such as CQRS, Strangler Fig, Branch by Abstraction, and feature toggles to support iterative, risk-based delivery.
• Develop and maintain integrations with external systems, data sources, APIs, and mission applications.
• Design and manage data models for Microsoft SQL Server and Oracle, including writing and optimizing high-performance T-SQL.
• Develop parsing and transformation solutions for complex data formats, including XML, XSLT, JSON-LD, and related structured data.
• Integrate software solutions with biometric devices, watch-listing technologies, and EBTS-compliant data sources.
• Support software and data solutions associated with Sensitive Site Exploitation (SSE) operations.
• Implement cybersecurity best practices throughout the development lifecycle, including secure coding, threat modeling, input validation, output encoding, secrets management, least-privilege access, and dependency/supply-chain risk management.
• Implement and maintain security controls aligned with NIST 800-53, DoD STIGs, and applicable Risk Management Framework (RMF) requirements.
• Support PKI-based authentication and access control and apply Zero Trust principles to application and data architectures.
• Protect Controlled Unclassified Information (CUI) through appropriate encryption and secure collection and transmission mechanisms, including HTTPS/SSL and PKI.
• Implement automated security testing practices, including SAST, DAST, and SCA, and support vulnerability remediation within established service-level requirements.
• Conduct code reviews, logging and auditing, vulnerability remediation, and other activities supporting secure software development and operational compliance.
• Leverage Azure cloud services and data-processing workflows to automate analytics, reporting, and mission-data exploitation capabilities.
• Support Azure DevOps CI/CD pipelines, automated testing, deployment automation, and continuous improvement of software delivery processes.
• Apply advanced prompt engineering and responsible AI practices to leverage Large Language Models (LLMs) for problem-solving, software development acceleration, and workflow automation while maintaining appropriate security guardrails.
• Evaluate and validate AI-generated solutions and implement secure integration patterns for AI-enabled capabilities.
• Provide software, database, and engineering support for enterprise environments spanning .com, NIPR, and SIPR networks.
• Troubleshoot application and server issues using system, application, and infrastructure logs and implement improvements that increase system reliability and availability.
• Support reliable worldwide access to mission-critical identity and intelligence data.
• Provide technical guidance for MOUs, MOAs, ISAs, and data-sharing agreements, translating mission and compliance requirements into technical controls and data-handling procedures.
• Produce and maintain architecture diagrams, software design documentation, engineering documentation, implementation plans, and sustainment procedures supporting development, accreditation, and lifecycle management.
• Maintain and transfer existing software licenses and development tools as necessary to ensure continuity of development operations.
• Collaborate with software engineers, database professionals, project managers, government stakeholders, and other technical teams to develop and implement effective mission solutions.
• Provide technical guidance and mentorship to other members of the engineering team as appropriate.

Minimum Requirements

• Bachelor’s degree in computer science, Software Engineering, Information Technology, or a related technical discipline; OR 4+ years of relevant professional software engineering experience.
• Demonstrated experience designing, developing, and sustaining enterprise software applications.
• Experience developing and integrating REST APIs, web applications, and backend services.
• Experience with modern software development practices and the full Software Development Lifecycle (SDLC).
• Experience with C#/.NET or comparable enterprise application development technologies.
• Experience working with relational databases, including Microsoft SQL Server and/or Oracle.
• Ability to obtain and maintain the required security clearance.
• Strong written and verbal communication skills.
• Ability to work effectively in an onsite, collaborative, mission-focused environment.

Required Skills

• Senior-level software engineering and application development experience.
• Strong experience with .NET application development and modernization.
• Experience developing REST APIs, background services, and enterprise applications.
• Experience with modern web development frameworks such as Vue.js, Nuxt, or comparable technologies.
• Strong understanding of Object-Oriented Design, Domain-Driven Design (DDD), and Test-Driven Development (TDD).
• Experience with software modernization and architectural patterns such as CQRS, Strangler Fig, Branch by Abstraction, and feature toggles.
• Experience with Microsoft SQL Server and/or Oracle, including database design, data modeling, and SQL performance optimization.
• Experience processing and transforming complex data formats such as XML, XSLT, JSON, or JSON-LD.
• Understanding of secure software development and DevSecOps practices.
• Experience implementing cybersecurity controls aligned with NIST 800-53, DoD STIGs, and RMF requirements.
• Familiarity with PKI, authentication and authorization, encryption, Zero Trust principles, and CUI protection.
• Experience with automated security and software testing, including SAST, DAST, and SCA.
• Experience with Azure and/or Azure DevOps, including CI/CD, automated testing, and deployment workflows.
• Ability to troubleshoot application and server issues using logs, monitoring data, and other diagnostic tools.
• Strong analytical and problem-solving abilities.
• Excellent verbal and written communication skills.

Preferred Qualifications

• Previous experience supporting DoD, Intelligence Community, Special Operations Forces, or other defense-related missions.
• Experience supporting identity intelligence, biometric systems, watch-listing technologies, or mission-data exploitation.
• Experience supporting Sensitive Site Exploitation (SSE) applications or data environments.
• Experience working across NIPR, SIPR, and enterprise (.com) environments.
• Experience With EBTS Specifications Or Other Biometric Data Standards.
• Experience modernizing legacy .NET Framework 4.7.x applications to modern .NET platforms.
• Experience with Vue.js, Nuxt, or comparable modern JavaScript frameworks.
• Experience implementing Zero Trust architectures and PKI-based authentication.
• Experience with cloud-based data processing, analytics, and reporting.
• Experience applying AI/LLM technologies, prompt engineering, and responsible AI practices to software development and workflow automation.
• Experience developing technical documentation supporting system accreditation, RMF, implementation, and sustainment.
• Experience working with MOUs, MOAs, ISAs, and other data-sharing agreements in a government or regulated environment.

This job description is intended to describe the general nature and level of work performed by employees in this position. It is not intended to be an exhaustive list of all responsibilities, duties, and skills required. Management retains the discretion to add to or modify the duties of the position at any time. Employment with Endurion is at-will, meaning that either the employee or the employer may terminate the employment relationship at any time, with or without cause or advance notice, provided it does not violate applicable law. Endurion complies with all Equal Employment Opportunity (EEO) requirements. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, veteran status, or any other legally protected characteristic. Endurion will provide reasonab