Sr Software Engineer Java Jobs in Illinois (NOW HIRING)

We are seeking a Senior Software Engineer to join a high-impact digital payments modernization program supporting the integration of a major card network into one of the largest financial institutions in the United States. This is a hands-on engineering role at the intersection of legacy and modern infrastructure, where you will contribute to both the reliability of mission-critical payment systems today and help shape the architecture that will power them tomorrow. You will work across scalable backend services, performance testing frameworks, and application engineering - with real opportunity to grow your skills on modern cloud-native technologies as the program evolves.

WHAT YOU'LL DO

You will be embedded across one or more workstreams supporting digital payments engineering, with responsibilities that may include:

Scalability, Performance Testing & Validation

• Design and execute enterprise-grade performance testing strategies for payment processing services, defining frameworks, tooling, and success criteria from the ground up.
• Identify performance bottlenecks across legacy and modern service layers and drive measurable improvements through analysis and targeted optimization.
• Instrument and validate services running on Java, Oracle, Tomcat, and WebSphere as well as modern workloads running on PostgreSQL and OpenShift.
• Collaborate with backend engineers to ensure scalability requirements are met across all environments prior to release.
• Translate performance findings into clear recommendations for engineering leads and stakeholders.

Application Engineering

• Build and maintain full-stack backend services supporting card network integration, working primarily in Java with PostgreSQL and OpenShift Container Platform (OCP).
• Contribute to application modernization efforts, migrating and re-platforming services from legacy infrastructure to cloud-native environments.
• Leverage AI-assisted development tooling (including GitHub Copilot) to improve development velocity and code quality.
• Participate in code reviews, architectural discussions, and cross-team technical planning sessions.

General Engineering

• PCI data purging pipelines and event-driven architecture patterns including token removal and event consumption.
• Work with event-driven services running on OpenShift and Oracle and PostgreSQL backends to support data lifecycle and compliance requirements.
• Serve as a flexible, senior contributor across teams where engineering depth and experience are needed most.

REQUIRED SKILLS & EXPERIENCE

Core Engineering

• 5+ years of professional software engineering experience, primarily in Java.
• Strong working knowledge of relational databases - Oracle and/or PostgreSQL required.
• Experience deploying and operating services in containerized environments (OpenShift, Kubernetes, or equivalent).
• Familiarity with legacy enterprise application servers - Tomcat and/or WebSphere experience a plus.

Performance Engineering 

• At least one enterprise-level performance testing engagement - defining strategy, selecting tooling, executing tests, and presenting findings.
• Experience with performance profiling, load testing, and bottleneck resolution in high-throughput, distributed systems.
• Ability to design logical, streamlined test frameworks from scratch and operate with minimal guidance.

Payments & Financial Services

• Background in digital payments, card processing, or financial services technology strongly preferred.
• Understanding of PCI compliance requirements and secure data handling practices.
• Familiarity with event-driven architecture patterns and OpenShift-based eventing.

Collaboration & Communication

• Demonstrated ability to work effectively in large, matrixed program environments with multiple teams and stakeholders.
• Strong written and verbal communication skills; able to translate technical complexity for non-technical audiences.
• Comfortable operating in environments with evolving requirements and ambiguity.

NICE TO HAVE

• Experience with PGLogical or PostgreSQL logical replication.
• Exposure to AI-assisted development tools (GitHub Copilot or Claude).
• Prior work on bank or card network integration programs.
• Experience working in segregated or air-gapped development environments.