Sr. Application Developer - Legacy System Modernization
Cass Information Systems
Full Time
Computer Occupations
Location
Bridgeton, Missouri, United States
Posted
July 08, 2026
Job Description
The Senior Application Developer – Legacy Modernization strengthens and evolves legacy systems by improving operational stability, enhancing observability, and migrating core services to modern, scalable platforms. This role designs and executes modernization strategies, establishes engineering standards, and leverages automation, CI/CD, and AI-assisted development tools to accelerate system transformation. It balances innovation with business continuity by improving system reliability, enabling efficient incident response, and managing technical risk across both legacy and modern environments.
PRINCIPAL RESPONSIBILITIES AND DUTIES: