Mid-Level Backend Software Engineer

Leidos Inc; St. Louis (MO); Hybrid; USD 87,100 - 157,450; Full time

Benefits offered by this job

Health and Wellness programs

Paid Leave and Retirement

Competitive compensation

Job summary

Leidos Inc in St. Louis is seeking a Backend Software Engineer to support high-visibility data-driven applications. You will design, develop, and maintain core backend services and RESTful APIs, enhancing system reliability and performance.

The ideal candidate will have a degree in Computer Science and experience with Java or Python. Join us for a role that supports mission-critical analytics across the organization.

Qualifications

• Bachelor's degree in Computer Science with 4-8 years experience.
• US Citizenship and active TS/SCI clearance are required.
• Professional experience in Java or Python for backend applications.

Responsibilities

• Design, develop, and maintain backend components using Java or Python.
• Create and support RESTful services for application functionality.
• Collaborate on data integration for backend systems.

Skills

Backend development

Java

Python

RESTful API development

SQL

Linux environments

Education

Bachelor's degree in Computer Science or related field

Master's degree in Computer Science or related field

Tools

Apache Airflow

Spring Boot

Django

CI/CD tools

Docker

AWS or Azure

Job description

Description

If you've been building your skills in backend development, object‑oriented programming, and mission‑driven engineering, and you're ready for work that actually moves the needle, this is the kind of opportunity cleared engineers pursue when they want to grow while making real impact. If you take pride in your craft, enjoy solving meaningful technical problems, and want your work to support a mission with visibility at senior levels, you'll thrive here.

We are hiring a Backend Software Engineer to support a high‑visibility, data‑driven application used across the organization for analytics and reporting. You will help build and maintain core backend services, develop RESTful APIs, support data‑driven functionality, and contribute to ongoing system enhancements within a Linux‑based environment. Your work will directly support system reliability, performance, and data accuracy for mission stakeholders. The primary development team operates out of Gaithersburg, MD, but we also support onsite engineers in Chantilly, VA, Alexandria, VA, Aurora, CO, St. Louis, MO, and Tucson, AZ, giving top talent multiple paths to join the mission.

Why This Role Stands Out

• High Impact: Your work supports a widely used application that drives real‑time decision‑making.
• High Visibility: Collaborate with engineering teams and mission stakeholders across programs.
• Career Growth: Build deeper expertise in backend development, API design, and scalable systems.
• Challenging Work: Contribute to complex backend features – not routine maintenance tasks.

Essential Responsibilities

• Backend Development: Design, develop, test, and maintain backend application components using Java or Python.
• REST API Development: Develop and maintain RESTful services to support application functionality and system integrations.
• Object‑Oriented Programming: Apply object‑oriented design principles to build scalable and maintainable systems.
• Database Development: Write and modify SQL queries to support application functionality and data retrieval.
• Data Source Collaboration: Collaborate with internal and external teams to understand data sources, formats, and access methods, and support integration into backend systems.
• Linux Environments: Develop and troubleshoot applications within Linux‑based environments.
• Data Processing & Business Logic: Implement backend logic for data transformation, processing, and system workflows.
• Bug Fixing & Enhancements: Identify, debug, and resolve application‑level defects and performance issues.
• Code Quality: Follow coding standards, participate in code reviews, and support documentation efforts.

Basic Qualifications

• Bachelor's degree in Computer Science, Software Engineering, or a related field with 4‑8 years of experience; or a Master's degree with 2‑6 years of experience.
• US Citizenship.
• Active TS/SCI with the ability to successfully pass a polygraph.
• Professional experience developing object‑oriented applications in Java or Python.
• Hands‑on experience building and maintaining RESTful APIs.
• Basic to moderate experience with SQL capability, including writing queries and working with relational databases.
• Working knowledge of Linux‑based environments.
• Ability to work independently on defined tasks within established technical frameworks and deliver reliable results.

Preferred Qualifications

• Experience with Apache Airflow or similar workflow orchestration technologies.
• Experience with Spring Boot, Django, or similar backend frameworks.
• Exposure to CI/CD pipelines (GitLab, Jenkins, etc.).
• Familiarity with containerization (Docker, OpenShift).
• Exposure to cloud environments (AWS or Azure).
• Experience working in Agile development environments.

Pay and Benefits

Pay Range: $87,100.00 - $157,450.00.

• Competitive compensation.
• Health and Wellness programs.
• Income Protection.
• Paid Leave and Retirement.

Commitment to Non‑Discrimination

All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.