Senior Python Developer (onsite)

System One; Washington, Northern (District of Columbia, KY); Hybrid; USD 130,000 - 170,000; Full time

Job summary

System One is seeking a Senior Application Developer (AWS/Python) in Washington, DC for 100% onsite work under a federal contract. U.S. citizenship and ability to obtain Public Trust clearance are required. W2 or C2C arrangements apply.

Responsibilities include developing Python microservices, building AWS infrastructure with CDK, and modeling complex workflows with Step Functions. Strong focus on testing, logging, and collaboration with stakeholders.

Qualifications

• BS in Computer Science/IT or equivalent experience.
• 7+ years of software development with SDLC and Agile.
• Production-grade Python development with modern frameworks and testing libraries.
• AWS Lambda, AWS Step Functions, DynamoDB, S3, API Gateway experience.

Responsibilities

• Develop and maintain Python-based microservices and AWS infrastructure using CDK.
• Model complex business workflows with AWS Step Functions.
• Build containerized applications with RESTful APIs.
• Conduct code reviews focused on maintainability and performance.
• Write unit tests and integration tests; perform code remediation.
• Collaborate with stakeholders to translate business requirements into technical solutions.

Skills

Python

AWS CDK

CI/CD

REST API design

Git workflows

Education

BS in Computer Science/IT

Tools

Terraform

CDK

Docker

GitLab

Job description

Senior Application Developer (AWS/Python)

Washington, DC – 100% Onsite

Per Federal contract U.S. citizenship is required

Must be able to obtain Public Trust clearance

W2 or C2C

Application Deadline: 9/10

Core Responsibilities:

Development & Infrastructure:

• Develop and maintain Python-based microservices and AWS infrastructure using CDK
• Model complex business workflows with AWS Step Functions
• Build containerized applications with RESTful APIs
• Implement comprehensive logging, monitoring, and audit trails (CloudWatch, CloudTrail)

Quality & Collaboration:

• Conduct code reviews focused on maintainability, performance, and best practices
• Write unit tests and integration tests; perform code remediation
• Contribute to architecture decisions and maintain technical documentation
• Collaborate with stakeholders to translate business requirements into technical solutions

Required Qualifications:

Core Technical Skills:

• Python: Production-grade development with modern frameworks and testing libraries
• AWS CDK: Infrastructure-as-code for multi‑environment deployments
• CI/CD: Hands‑on pipeline creation and management for cloud applications
• API Design: RESTful service design, versioning, and error handling
• Version Control: Git workflows, branching strategies, merge request reviews

Technical Stack:

Primary (daily use expected):

• Python 3.9+, AWS Lambda, Step Functions
• IaC: CDK, Terraform experience
• DynamoDB, S3, API Gateway, CloudWatch, CloudTrail
• Docker, Git/GitLab

Secondary (nice to have):

• Frontend: Angular or React (TypeScript)
• AWS Services: SNS/SQS, Athena, Glue, Load Balancers

Productivity Tools (Plus):

• AI-Assisted Development
• Experience using AI coding assistants such as Claude Code for:
  • Code review and optimization suggestions
  • Documentation generation
  • Debugging and troubleshooting
  • Test case development
• Ability to critically evaluate and adapt AI-generated code

Education & Experience:

• BS in Computer Science/IT or equivalent work experience
• 7+ years software development experience with SDLC and Agile methodologies

System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.

System One is an Equal Opportunity Employer.

All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.

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