Full-Stack Engineer, Agentic Development

Expression is seeking a Full Stack Engineer to develop and deliver software across our federal mission systems using AI coding agents as a primary development tool. This role spans web interfaces, backend services and APIs, databases, and the containers and pipelines used to deploy applications to AWS.

You will direct agents such as Claude Code, OpenAI Codex, and Factory’s Droids to perform much of the implementation while taking responsibility for planning, technical decisions, code review, testing, and the quality of every change. You will also use AI to explore unfamiliar codebases, evaluate technologies, and develop proofs of concept that help the team make informed decisions.

The ideal candidate combines strong software engineering fundamentals with practical experience using AI agents. You can recognize when generated code is incorrect, insecure, or incomplete, and you can perform the work independently when AI tools are unavailable. You bring initiative, identify opportunities for improvement, and follow through on proposed solutions.

In this role, you will collaborate with senior engineers, technical leads, product owners, and end users. You will own clearly scoped features from planning through deployment, with opportunities to take on broader design responsibilities as you grow.

Clearance: Eligible for Secret clearance or higher is required.

Location: Hybrid in the DMV or remote role with onsite work at Expression HQ and client site as needed. If remote, travel would be required a few times per year.

Key Responsibilities

Full Stack Development

• Develop features across the application stack, including React interfaces, Node.js and Python services, REST APIs, and relational and MongoDB data models.
• Own assigned features from requirements clarification and implementation through testing, deployment, and documentation.
• Write and maintain unit, integration, and end-to-end tests.
• Troubleshoot issues across application layers, identify root causes, and implement fixes with tests or monitoring to prevent recurrence.

AI-Assisted Engineering and Technical Evaluation

• Direct AI coding agents through clear task descriptions, implementation plans, and acceptance criteria.
• Review, test, and correct agent-generated code to ensure it meets functional, security, maintainability, and performance requirements.
• Use AI to research unfamiliar code, libraries, and services; compare technical approaches; and document recommendations and tradeoffs.
• Develop proofs of concept to validate ideas and reduce design risk, then mature approved approaches into production software with appropriate tests, CI/CD, and documentation.
• Help maintain agent instructions, prompts, and reusable skills to improve the team’s development practices.

Deployment, Operations, and Security

• Package applications using Docker and build and maintain CI/CD pipelines that test, scan, and deploy software.
• Deploy and support services on AWS, coordinating infrastructure and security changes with senior engineers.
• Contribute to security hardening and Security Technical Implementation Guide (STIG) evidence.
• Maintain documentation that enables other engineers and their AI tools to understand, operate, and support the software.

Collaboration and Continuous Improvement

• Collaborate with engineers, technical leads, product owners, and end users to clarify needs and deliver practical solutions.
• Proactively identify issues such as unreliable tests, slow application performance, manual processes, and documentation gaps.
• Propose improvements, communicate their value and tradeoffs, and carry approved changes through completion.

Required Qualifications

• Bachelor’s degree in Computer Science, Software Engineering, Information Technology, or a related field, or equivalent professional experience.
• At least three years of professional software engineering experience.
• Strong programming skills in JavaScript, TypeScript, and Python.
• Hands-on experience developing both web interfaces using React or a similar framework and backend services or REST APIs using Node.js, Python, or similar technologies.
• Strong understanding of:
  • Browsers, HTTP, REST APIs, and authentication.
  • Relational data modeling and SQL.
  • Core data structures and algorithms.
  • Software testing and debugging.
  • Common application security risks, including the OWASP Top 10.
  • Linux command-line tools, Bash scripting, and Git.
• Hands-on experience with MongoDB or a similar document database, including document schema design, queries, aggregations, and index selection.
• Hands-on Docker experience, including writing Dockerfiles, troubleshooting image builds, and running multi-container applications with Docker Compose.
• Experience building or modifying CI/CD pipelines using GitLab CI, GitHub Actions, or similar platforms.
• Hands-on experience deploying applications to AWS using services such as EC2, S3, and RDS, with a working understanding of IAM and VPC networking.
• Regular, hands-on use of AI coding agents, such as Claude Code, OpenAI Codex, Factory’s Droids, or similar tools, for most implementation work. Experience must include directing agents that read code, run commands, and make changes, with independent verification through testing, code review, and comparison against requirements. Personal and open-source projects qualify; autocomplete-only experience does not meet this requirement.
• Experience with Elasticsearch, including index mappings, search queries, and aggregations.
• Experience with PostgreSQL.
• Experience using Python for ETL, data pipelines, or migrations, including validation and reconciliation of results.
• Experience using AI for technical research, evaluation, or proofs of concept, such as exploring an unfamiliar codebase, comparing libraries, or prototyping a proposed solution.
• Demonstrated initiative through independently identifying problems, proposing improvements, and delivering solutions.
• Clear written communication skills, including the ability to prepare precise instructions, explain technical decisions, and present recommendations.
• Ability to develop, troubleshoot, and maintain software when AI tools are unavailable.

Preferred Qualifications

• Experience developing agent instructions, prompts, or reusable skills, including CLAUDE.md or AGENTS.md files, custom commands, or Model Context Protocol (MCP) servers.
• Experience preparing design documents or technical proposals and guiding them through review.
• Experience configuring AWS infrastructure, including IAM policies and VPC networks.
• Experience with infrastructure as code tools such as Terraform or CloudFormation, or with AWS GovCloud
• Experience with Playwright or another end-to-end testing framework.
• Experience with Keycloak or another identity and access management platform.
• Experience with additional languages or frameworks, such as Java, Angular, or PySpark.
• Experience working in air-gapped or other restricted environments.
• Experience supporting Department of Defense or other federal customers, including STIG requirements and classification marking requirements.

Benefits:

Expression offers competitive salaries and benefits, such as:

• 401k matching
• PPO and HDHP medical/dental/vision insurance
• Education reimbursement
• Complimentary life insurance
• Generous PTO and holiday leave
• Onsite office gym access
• Commuter Benefits Plan

About Expression: 

Founded in 1997 and headquartered in Washington DC, Expression provides data fusion, data analytics, AI/ML, software engineering, information technology, and electromagnetic spectrum management solutions to the U.S. Department of Defense, Department of State, and national security community. Expression’s culture focuses on creating immediate and sustainable value for our clients via agile delivery of tailored solutions built through constant engagement with our clients. Expression was ranked #1 on the Washington Technology 2018's Fast 50 list of fastest-growing small business Government contractors and a Top 20 Big Data Solutions Provider by CIO Review.

We make sure to provide everyone with the tools and opportunities to grow while working on some of the newest technologies in the industry. We get excited about celebrating our professionals' milestones, accomplishments, promotions, overcoming challenges, and many other aspects that make an engaging collaborative environment.

Equal Opportunity Employer/Veterans/Disabled
Expression is an Equal Opportunity Employer. If you require a reasonable accommodation during the application or interview process, please submit your request to our Human Resources department through the application portal.