Senior Java Engineer: Connex Payment Switch & Microservices

Greymatter Innovationz; Chicago (IL); On-site; USD 120,000 - 160,000; Full time

Job summary

Greymatter Innovationz in Chicago, IL is seeking a Senior Java Developer with expertise in Connex Payment Switch to lead design and development of high-volume payment applications.

You will build Java/Spring Boot microservices, integrate with external banking networks, and handle performance optimization for mission-critical transaction systems, requiring 8+ years in Java development.

Qualifications

• 8+ years of Java development experience.
• Experience with Connex Payment Switch and ISO 8583 messaging.
• Proficiency in Java/Spring Boot microservices and REST APIs.
• Strong in CI/CD, Git, Linux/Unix stack.
• Database expertise with Oracle/SQL Server/PostgreSQL.

Responsibilities

• Design, develop, and maintain high-volume Connex Payment Switch applications.
• Support transaction processing for credit, debit, ATM, POS, and digital channels.
• Build scalable Java/Spring Boot microservices and integrate with banking networks.
• Handle production support, root cause analysis, and performance optimization.

Skills

Core Java

Spring Boot

Microservices

REST APIs

CI/CD

Git

Linux/Unix

Connex Switch

ISO8583

EMV

Card payments

ATM/POS

Tools

Oracle

SQL Server

PostgreSQL

Job description

Greymatter Innovationz in Chicago, IL is seeking a Senior Java Developer with expertise in Connex Payment Switch to lead design and development of high-volume payment applications.

You will build Java/Spring Boot microservices, integrate with external banking networks, and handle performance optimization for mission-critical transaction systems, requiring 8+ years in Java development.