C1: GPN - Java Engineers for ARP/ETB Integration

Kunai; United States; Remote; USD 150,000 - 230,000; Full time

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.

Skills

Java

PostgreSQL

OpenShift

Kubernetes

Spring Boot

JPA

Kafka

Apache Camel

Drools

OAuth2/OIDC

React

TypeScript

AWS IAM

CI/CD

Performance testing

Distributed systems

Domain-driven design

Authorization

Education

Bachelor's Degree

Tools

Liquibase

Okta

GitHub Copilot

Job description

Kunai builds full-stack technology solutions for banks, credit and payment networks, infrastructure providers, and their customers. Together, we are changing the world’s relationship with financial services. At Kunai, we help our clients modernize, capitalize on emerging trends, and evolve their business for the coming decades by remaining tech-agnostic and human-centered.

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.

Some things you may work on

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

Domain & Service Architecture

• Apply domain-driven design to define bounded contexts, domain models, and aggregate boundaries for card-network reference data — establishing a ubiquitous language shared across engineering and business stakeholders.
• Develop and harden a Spring Boot / JPA / PostgreSQL Aurora service with Liquibase-managed schema migrations, a Drools-based business rules engine, and scheduled batch jobs — including designing authorization and data-access controls from the ground up where none exist today.
• Design and own integration workflows and routing using Apache Camel (or equivalent), orchestrating multi-step, stateful operations such as request intake, validation, approval, and publication pipelines.
• Develop an event-driven backbone using Kafka — topic/schema design, producer/consumer reliability patterns, and integration with the rules engine and workflow layer.

Frontend & Identity

• Develop a micro-frontend application (Next.js/React/TypeScript) as an independently deployable system, and design its convergence path into the card network’s future shared micro-frontend shell.
• Own the OAuth2/OIDC identity architecture end-to-end — provider integration (Okta), JWT/token validation strategy, session/revocation design, and trust-boundary decisions across environments.

Cloud & Platform

• Design and govern AWS IAM policy, S3, and CloudFront architecture across multiple environments — this is not config-following; you’re expected to set the standard.
• Lead deployment on the organization’s internal static cloud hosting platform.
• Drive test-driven development practice across the team and build out continuous testing/automation pipelines (unit, contract, integration, and end-to-end) as part of CI/CD.

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; hands-on experience with PostgreSQL Aurora and Liquibase-managed migrations a strong plus.
• 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.
• Experience with Spring Boot/JPA, business rules engines (e.g., Drools), and integration/orchestration frameworks (e.g., Apache Camel).
• Working knowledge of Kafka or similar event-streaming platforms, including topic/schema design and producer/consumer reliability patterns.

Architecture & Design

• Practical experience applying domain-driven design — bounded contexts, aggregates, and ubiquitous language — in a production system.
• Demonstrated ownership of authorization/data-access control design, not just implementation against an existing model.
• Experience designing and governing cloud IAM, storage, and CDN architecture (AWS IAM, S3, CloudFront or equivalents) at a standards-setting level.

Frontend & Identity

• Experience with modern frontend frameworks (Next.js/React/TypeScript), including micro-frontend architectures and independently deployable frontend systems.
• Experience owning OAuth2/OIDC identity flows end-to-end, including provider integration (e.g., Okta), token validation, and session/revocation design.

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.

Testing & CI/CD

• Demonstrated experience driving test-driven development practices across a team.
• Experience building continuous testing/automation pipelines (unit, contract, integration, and end-to-end) as part of CI/CD.

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.

At this time we are unable to provide sponsorship for this role.

Our success over the past 20 years is rooted in our exceptional team, which thrives in a culture of collaboration, creativity, and continuous learning.

We are proud to offer our employees a range of benefits, including competitive compensation, professional development opportunities, and flexible work arrangements, all designed to help them thrive. As we continue to expand, we remain committed to cultivating an environment where people feel valued, have a voice, and are given the tools to grow—both personally and professionally—while pushing the boundaries of innovation in the fintech industry.

Minimum Degree Required:

• Bachelor’s Degree, in lieu of a degree, demonstrating in addition to the minimum years of experience required for the role, three years of specialized training and/or progressively responsible work experience in technology for each missing year of college isrequired