Senior Java Engineer — Card Network Integration & Payments

Kunai

United States

Remote

USD 150,000 - 230,000

Full time

5 days ago

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Job summary

Kunai, a fintech-focused engineering partner, is seeking a Senior Software Engineer to contribute to a high-impact digital payments modernization program integrating a major card network for a large US financial institution. This hands-on role spans backend services, frontend microfrontends, and cloud platforms, emphasizing reliability and scalable architecture.

You will own and evolve systems in Java, Spring Boot, PostgreSQL, OpenShift, and modern frontend stacks (Next.js/React/TypeScript),

Qualifications

5+ years of professional software engineering experience, primarily in Java.
Strong working knowledge of relational databases — Oracle and/or PostgreSQL required; PostgreSQL Aurora + Liquibase migrations a strong plus.
Experience deploying and operating services in containerized environments (OpenShift, Kubernetes).
Familiarity with legacy enterprise application servers — Tomcat and/or WebSphere experience a plus.
Experience with Spring Boot/JPA, business rules engines (Drools), and integration/orchestration frameworks (Apache Camel).
Working knowledge of Kafka or similar event-streaming platforms, including topic/schema design and producer/consumer reliability patterns.

Responsibilities

Develop and harden a Spring Boot / JPA / PostgreSQL Aurora service with Liquibase migrations and a Drools-based rules engine.
Design and own integration workflows and routing using Apache Camel.
Develop an event-driven backbone using Kafka and integrate with the rules engine and workflow layer.
Build a micro-frontend with Next.js/React/TypeScript as an independently deployable system.
Own OAuth2/OIDC identity architecture end-to-end (Okta), token validation, and session design.