Lead Java Engineer (Onsite) O''Fallon, MO

• Work Model: Onsite
• In Person Interview

Job Summary

We are seeking a highly skilled and results-driven Lead Java Engineer to lead the design, development, and delivery of mission-critical payment and transaction processing platforms. The ideal candidate will possess deep expertise in Java-based distributed systems, microservices architecture, cloud technologies, and high-volume transaction processing. This role requires a hands-on technical leader who can drive architecture decisions, mentor engineering teams, and deliver highly secure, scalable, and resilient solutions.

Key Responsibilities

• Lead the design, development, and implementation of enterprise-grade applications supporting high-volume transaction processing.
• Architect and build scalable, low-latency, highly available microservices using Java and Spring technologies.
• Collaborate with product managers, architects, business stakeholders, and engineering teams to deliver strategic technology initiatives.
• Drive modernization efforts by migrating monolithic applications to cloud-native architectures.
• Establish engineering best practices, coding standards, design principles, and quality controls across development teams.
• Lead code reviews and provide technical mentorship to developers.
• Design solutions that meet stringent security, compliance, performance, and resiliency requirements.
• Develop and optimize APIs and event-driven services supporting real-time integrations.
• Troubleshoot and resolve complex production issues in distributed environments.
• Partner with DevOps teams to implement CI/CD pipelines, monitoring, and observability practices.
• Contribute to architectural roadmaps and technology strategy discussions.

Required Qualifications

• Bachelor's degree in Computer Science, Engineering, or related discipline.
• 15+ years of software engineering experience with strong expertise in Java development.
• 3+ years of experience leading engineering teams or technical initiatives.
• Extensive experience with:
  • Java 11/17+
  • Spring Boot
  • Spring Cloud
  • RESTful APIs
  • Microservices Architecture
  • Design Patterns
  • Distributed Systems
  • Multithreading and Concurrency
• Strong experience with relational and NoSQL databases.
• Hands-on experience developing high-availability and fault-tolerant systems.
• Strong understanding of secure application development and API security.
• Experience with Agile software development methodologies.

Preferred Qualifications

• Experience working in payment processing, financial services, banking, fintech, or transaction-intensive environments.
• Experience developing systems handling millions of transactions per day.
• Knowledge of payment lifecycle, authorization, clearing, settlement, fraud prevention, or risk management systems.
• Experience with event-driven architectures and real-time messaging frameworks.
• Experience implementing globally distributed and highly resilient systems.

Leadership Expectations

• Serve as a technical leader and trusted advisor for engineering teams.
• Mentor engineers and promote a culture of technical excellence.
• Drive architectural decisions and ensure alignment with enterprise standards.
• Collaborate across teams to deliver scalable and reliable solutions.
• Champion innovation, automation, and continuous improvement initiatives.
• Influence long-term technology strategy and engineering best practices.

Nice to Have

• Experience with ISO 8583, payment gateways, card processing, digital payments, or real-time transaction networks.
• Knowledge of PCI-DSS, SOX, and financial compliance regulations.
• Experience building global, mission-critical platforms with 24x7 availability requirements.
• Exposure to AI-assisted development, performance engineering, and platform modernization initiatives.