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Senior Software Engineer (Java)

Role overview

Qualifications

  • 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.

Responsibilities

  • Design and execute enterprise-grade performance testing strategies for payment processing services.
  • Build and maintain full-stack backend services supporting card network integration.
  • Work with event-driven services running on OpenShift and Oracle and PostgreSQL backends.
  • Serve as a flexible, senior contributor across teams where engineering depth and experience are needed most.

About the company

Kunai logo

Kunai

Information Technology & Services

Kunai Co. is a team of developers, designers, and product managers building seamless customer experiences that unite digital products with FinTech. Kunai concepts, designs, and develops unique digital products and payment experiences for the world's top companies. Starting in 1999, Kunai helped Cisco Systems prepare for Y2K, and then in 2006, built the world's first touchscreen PC. Later, Kunai designed and developed some of the world's first successful iOS apps. With Capital One’s acquisition in 2015, we focused on fintech and how to build on a massive scale, so a portion of our team rebranded as Kunai and continued to refine our approach to product development. Over 20 years, Kunai shipped over 150 digital products that are trusted by Fortune 500 companies and unicorn startups alike. Kunai's founders, being former bank executives, started the company with the insights of years-long struggles to hire developer talent. As a result, only the top 3% of developers worldwide make it onto a Kunai team. What we do: Technical Staffing: The Kunai Direct Sourcing Platform helps companies to find, vet, interview, and onboard the world’s best developers. Kunai works on a range of technologies and platforms and has deep experience in fintech and leverages industry-leading APIs and practices. Digital product development for fintech: Kunai understands the unique needs of financial services companies. We're a digital product development consultancy focused on fintech. Kunai handles product management, design, development, cloud management, and much more to build your next new idea into a prototype faster. We build long-term relationships with our clients. Our portfolio includes all four major payment networks, four top ten US banks, seven Fortune 500 technology companies, and ten unicorn startups. If you have an idea and need a team that can make it a reality, we should talk.

Company details

Company typeScaleup
IndustryInformation Technology & Services
Company size201 - 500

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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. 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.
 

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 is required

 

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MR

Marcus Rivera

Chief Revenue Officer

m.rivera@company.com
linkedin.com/in/marcusrivera
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