Principal Software Engineer

Leidos is seeking a TS/SCI cleared Principal Software Engineer to support the DIA-NDOC DOMEX Technology Platform (DTP) contract, building secure, observable services for the team.

Responsibilities

• Design, develop, test, and maintain Python microservices
• Implement message consumers and producers using Apache Kafka
• Integrate Elasticsearch for real-time and batch data indexing and querying
• Write unit and integration tests to support high code coverage and reliability
• Build CI/CD pipelines for services and deploy to Kubernetes clusters
• Participate in design discussions, code reviews, and architecture planning
• Monitor and troubleshoot production issues using observability tools
• Contribute to technical documentation and knowledge sharing
• Use software engineering and design methodologies appropriate to development, integration, and production environments
• Support a collaborative team culture focused on quality service and product delivery

Requirements

• Bachelor’s Degree and 12+ years of relevant experience, or Master’s with 10+ years; relevant experience may be considered in lieu of a degree
• Must hold an Active Top Secret/SCI clearance and be able to obtain and maintain a Polygraph
• Proficiency in Python and backend frameworks such as FastAPI or Flask
• Experience with containerization, especially Docker
• Hands-on experience with ETL (Extraction, Transformation, Load)
• Linux development experience, including bash or bash-like scripting
• Strong understanding of RESTful APIs and microservice architecture
• Hands-on experience with Kubernetes, including deploying, monitoring, and debugging services
• Understanding of design patterns, security practices, and logging/monitoring principles
• Familiarity with Git and collaborative workflows (PRs, reviews)
• DevOps practices and CI/CD tools and practices, especially GitLab or Jenkins
• Strong verbal and written communication skills
• Experience with Agile practices
• Team-oriented self-starter approach

Technologies

• Python, FastAPI, Flask
• Apache Kafka
• Elasticsearch
• Kubernetes
• Docker
• Linux, bash
• RESTful APIs
• Git
• CI/CD, GitLab, Jenkins
• ETL

Nice to Have

• Experience designing and implementing software development kits
• Familiarity with DGX (Deep GPU Xceleration)
• Active Security+ certification and ability to obtain Privileged User Account (PUA) certification by the Government
• Elasticsearch certifications or other program stack related certifications
• Experience with production/enterprise systems at scale
• Knowledge of distributed systems concepts (e.g., idempotency, eventual consistency)
• Familiarity with schema registries and Kafka streaming patterns
• Experience blending analytical methodologies and leveraging existing COTS/GOTS/OS tools in unconventional ways
• Experience with Amazon Web Services (AWS/C2S)
• Familiarity or experience building applications around Large Language Models and agentic AI

Location

• Onsite in Bethesda, MD

Schedule Note

• Most work is conducted onsite at the client location in Bethesda, MD
• A flexible schedule is offered
• Percentage of remote work will vary based on client requirements/deliverables

Pay Range

• USD 131,300 - 237,350 per year

Benefits

• Health and Wellness programs
• Income Protection
• Paid Leave
• Retirement

Posting Details

• Original posting date: September 22, 2026
• For U.S. positions: Leidos reasonably anticipates this requisition will remain open for at least 3 days with an anticipated close date no earlier than 3 days after the original posting date