Java Developer with Credit Card Payments Experience

Java Developer with Credit Card Payments Experience (ISO 8583 required)
Dallas, TX or Atlanta, GA or Phoenix, AZ or St Louis, MO or Chicago, IL (onsite 3 days a week)
1 year + contract

Has a well-developed prototype that takes data from Excel (ingested from transaction applications), analyzes the data and pushes out the corresponding transaction message. Has an injector function (injection of transactional data) and responded, but both are not complete and need to be build out.

Needs a hands-on developer, Senior individual contributor who has taken applications to production
Intake of ISO messages through the systems, converted data format and ingests data to Excel. Java product on top of that converts into message outputs. C /XML for file exchange
Using Java/Spring Boot for all services
REST APIs
ISO8583 protocol needed for transactional data
Unit testing required (Java code, Junit or similar)
UI us a plus but not required
Nice to have HP Nonstop background
Nice to have Linux