Senior Developer

Castello Systems, Inc.; Corridor North (MD); On-site; USD 120,000 - 170,000; Full time

Job summary

Castello Systems, Inc. seeks a senior full-stack engineer to lead a small development team focused on sustaining and enhancing a mission-critical Enterprise Support Services application.

You will translate customer needs into technical requirements and deliver scalable, secure applications. You will collaborate with customers and stakeholders, build responsive web interfaces, and integrate backend services via RESTful APIs using Django/FastAPI/Flask and React.js or Vue.js.

Qualifications

• Hands-on experience with Python web frameworks (Django, FastAPI, Flask).
• Strong front-end skills in modern JavaScript frameworks (React.js, Vue.js).
• Experience building RESTful APIs and integrating backend services.

Responsibilities

• Lead a small development team supporting sustainment and enhancement of enterprise software.
• Translate customer needs into technical requirements and solutions.
• Engage with customers and stakeholders to align on business needs and technical approaches.
• Build intuitive, responsive web interfaces with robust data handling.
• Develop and maintain Python backend services and JavaScript front-ends.

Skills

Python

Django

FastAPI

Flask

React.js

Vue.js

RESTful APIs

PostgreSQL

Oracle

SQL Server

Git/GitLab

CI/CD

Docker

Linux

Agile/Scrum

Tools

Git/GitLab

CI/CD

Docker

Job description

• Lead a small, collaborative development team supporting the sustainment and continuous enhancement of a mission-critical Enterprise Support Services application that enables a key operation.
• Serve as a senior technical point of contact between the development team and the customer, helping translate customer needs into clear, actionable technical requirements and solutions.
• Engage with customers and stakeholders to understand business needs, communicate technical approaches, refine requirements, and build alignment and buy-in for proposed solutions.
• Build intuitive, responsive web interfaces backed by robust data retrieval and storage capabilities.
• Apply hands-on expertise with modern Python frameworks - such as Django, FastAPI, or Flask - to deliver scalable, secure, and performant applications.
• Apply hands-on expertise with modern JavaScript and front-end frameworks, specifically React.js and Vue.js, to deliver high-quality user interfaces and dynamic, client-side application features.
• Integrate backend services through RESTful APIs to support seamless data flow and reliable application functionality.
• Leverage full-stack development skills across Python backend services and modern JavaScript front-end architectures to deliver scalable, end-to-end solutions.
• Demonstrate strong experience with relational database management systems (RDBMS), with primary expertise in PostgreSQL and secondary experience with Oracle and SQL Server.
• Translate complex business requirements into effective enhancements within existing database structures and application logic.
• Support and execute application upgrades while implementing code enhancements that improve performance, maintainability, and long-term sustainability.
• Develop efficient data retrieval solutions that power user-friendly displays and dynamic application views.
• Diagnose, troubleshoot, and resolve application defects to help maintain system stability and a positive user experience.
• Design, build, and deploy Dock containerized applications to Linux servers.
• Conduct thorough unit testing to validate software reliability, performance, and feature accurac y.
• Collaborate within Git/GitLab workflows and contribute to CI/CD pipelines that enable smooth, automated, delivery of application updates.
• Bring a proactive, ownership-oriented approach to problem-solving, provide technical leadership to the development teams, and demonstrate a strong willingness to take on new challenges and learn emerging technologies.
• Actively contribute in an Agile environment by participating in sprint planning, backlog grooming, and iterative development cycles that deliver continuous value.