Senior Software Engineer (Java)

Kunai

About The Position

Kunai is seeking a Senior Software Engineer to join a high-impact digital payments modernization program. This role supports the integration of a major card network into a large financial institution in the United States. It is a hands-on engineering position at the intersection of legacy and modern infrastructure, contributing to the reliability of mission-critical payment systems and shaping future architecture. The engineer will work across scalable backend services, performance testing frameworks, and application engineering, with opportunities to grow skills in modern cloud-native technologies.

Requirements

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).
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.
Understanding of PCI compliance requirements and secure data handling practices.
Familiarity with event-driven architecture patterns and OpenShift-based eventing.
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 Haves

Familiarity with legacy enterprise application servers — Tomcat and/or WebSphere experience a plus.
Background in digital payments, card processing, or financial services technology strongly preferred.
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.

Responsibilities

Design and execute enterprise-grade performance testing strategies for payment processing services, defining frameworks, tooling, and success criteria.
Identify performance bottlenecks across legacy and modern service layers and drive measurable improvements.
Instrument and validate services running on Java, Oracle, Tomcat, and WebSphere, as well as modern workloads 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.
Build and maintain full-stack backend services supporting card network integration, 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.
Work with 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.