Engineer Level 3

Advanced Software Engineer Level 3

Lead Stack Inc. is an award winning, one of the nation's fastest growing, certified minority owned (MBE) staffing services provider of contingent workforce. As a recognized industry leader in contingent workforce solutions and Certified as a Great Place to Work we're proud to partner with some of the most admired Fortune 500 brands in the world.

Location:

Blue Ash, OH – Onsite Duration: 6 Month(s)

Employment Type:

Contractor Senior-level experience developing enterprise Java applications. Strong hands-on experience with Java, Spring, and Spring Boot. Experience developing RESTful APIs and backend microservices. Experience with API Gateway integration and enterprise system integrations. Hands-on Point-of-Sale (POS) experience, including working directly with POS terminals or related test environments. Experience working in PCI-scoped, payment, financial, or other security-sensitive environments. Ability to work effectively onsite with cross-functional technical teams.

Technology Stack

Required:

Java, Spring, Spring Boot, REST APIs, API Gateway, Microservices, POS Integration, PCI/Secure Development Practices

We are seeking an Advanced Software Engineer to join a newly established team supporting the Omnichannel Payment Platform (OPP) and a new Point-of-Sale (POS) system. This senior-level consultant will play a critical role in stabilizing the new POS environment and integrating it with OPP. The ideal candidate will have strong hands-on experience with Java, Spring/Spring Boot, backend services, API Gateway integrations, and enterprise payment systems, along with practical POS experience.

Experience working in PCI-scoped environments is highly valued.

• Design, develop, and maintain backend services using Java and Spring Boot.
• Support the integration of the new POS platform with the Omnichannel Payment Platform (OPP).
• Develop and support integrations with enterprise API Gateway platforms and downstream services.
• Troubleshoot and stabilize POS-to-backend and payment processing integrations.
• Perform hands-on testing and troubleshooting using physical POS terminals and test hardware in the onsite POS lab.
• Develop secure, scalable, and highly available backend services.
• Work within PCI-scoped environments, adhering to applicable security and compliance standards.
• Collaborate with POS, payment, architecture, QA, Dev Ops, and product teams to resolve integration issues and accelerate delivery.
• Participate in technical design, code reviews, troubleshooting, and architecture discussions.
• Develop automated unit and integration tests to ensure reliable and maintainable solutions.
• Investigate complex integration and production issues and drive them through resolution.
• Support event-driven architectures and messaging technologies as required.
• Help establish development and integration practices for the newly formed OPP/POS team
• Preferred:
  Kafka, Event-Driven Architecture, Payment Systems, CI/CD, Cloud, Containers