Senior Full Stack Engineer

Remote from: USA
Salary, yearly, USD: 135,000 - 175,000
Department: Software Engineering
Employment type: Full Time,
Job posted: 16 Sep 2025
Apply before: 16 Oct 2025
Experience level: Senior
Views / Applies: 94 / 32

About ECS

Partnering with leading organizations to deliver powerful solutions for a complex world.

Actively Hiring

ECS is seeking a highly skilled Senior Full Stack Engineer to work remote or in the Washington, DC metropolitan area with extensive experience in designing, building and maintaining large-scale API’s for enterprise level applications in support of the Department of Homeland Security. Tools necessary for excelling in this role include Java (with Maven, Gradle, etc), JavaScript Frontend frameworks (React, Angular, etc), Elastic and other data sources, and DevSecOps in the Cloud. This role will focus heavily on modernizing legacy systems with deprecated code bases, requiring both technical expertise and creative problem-solving abilities. You will play a critical role in rearchitecting our application’s API infrastructure, ensuring scalability, reliability and long-term maintainability.

Key Responsibilities:

Support the design and architecture of robust, scalable API’s for large enterprise level applications.
Integrate and operate CI/CD pipelines used for building and releasing code and container images.
Assess and refactor deprecated code bases implementing best practices for modernization and performance improvement.
Collaborate with engineers to integrate React-based user interfaces with scalable APIs, leveraging React expertise to enhance API interactions, support legacy system modernization, and ensure seamless functionality and optimal user experience.
Provide solutions for legacy system migration while minimizing system downtime and operational risks.
Identify and resolve technical debt in older systems while transitioning them to modern Java frameworks and tools.

Salary Range: $135,000 – $175,000

General Description of Benefits

Qualifications

Master’s degree in a relevant field
12+ years’ work experience
Ability to pass a Public Trust background check
8+ years with Java (8 and beyond) with strong experience in legacy system modernization.
Has successfully performed code refactoring of deprecated codebases, developed backward compatibility and technical debt reduction.
3+ years of experience with Springboot or other stateless Java frameworks
5+ years developing restful API design microservices and service-oriented architecture.
3+ years of experience working with CI/CD pipelines and deploying and operating in cloud platforms
5+ years’ experience with relational databases and ORM technologies, experience with ElasticSearch or Opensearch a plus.
3+ years developing applications in a production setting and troubleshooting complex issues within legacy environments and proposing effective solutions.
Excellent communication skills with the ability to explain technical challenges and solutions to non-technical stakeholders.

Apply now >