Senior Java Full Stack Developer

Job Title:Senior Java Full Stack Developer
Location: O Fallon, MO
Type: W2 Contract (NO OPTs)

***Only qualified Senior Java Full Stack Developer located near O'Fallon MO to be considered due to the position requiring a hybrid presence. ***

Industry: Payments LOCAL CANDIDATES PREFERRED!




Education:
Bachelor's degree in information systems, Information Technology, Computer Science, Engineering, or equivalent work experience.




Required Skills & Experience:
More than 7 years of industry experience.
Excellent communication skills, with the ability to interact across multiple organizational levels and with internal and external customer groups.
Strong analytical and problem-solving abilities, with the ability to quickly adapt to new technologies, methodologies, and systems.
High energy, strong attention to detail, and the ability to function independently under pressure with a high degree of initiative and self-motivation.
Strong interpersonal and relationship-building skills, with a solid track record of developing internal and external partnerships.
Proficiency with J2EE, Java 8 or higher, JSP, Servlets, Spring 5, Hibernate, and databases such as Oracle and SQL Server.
Experience with SQL and NoSQL databases such as MySQL, PostgreSQL, and MongoDB.
Experience with web services (SOAP/RESTful), servers (WebSphere, JBoss, Tomcat), HTML, JavaScript, jQuery, React or Angular, and IDEs such as Microsoft Visual Studio or Eclipse is a plus.
Experience with tools such as Maven, Gradle, Jenkins, Chef, and Sonar, as well as methodologies such as Waterfall and Agile.
Experience with LLM integration, prompt engineering, and agentic patterns.
Java Full Stack Engineering
o Java 8+, J2EE, Spring, Hibernate
o Angular/React front-end development
o REST/SOAP APIs and enterprise application development
Cloud-Native Architecture & DevOps
o Cloud-Native / AWS or Other Cloud Platforms
o CI/CD and engineering tools like Jenkins, Maven, Gradle, Chef, and Sonar
GenAI / AI-Enabled Engineering
o Ability to leverage GenAI tools to improve developer productivity
o Apply AI-assisted coding, testing, documentation, and troubleshooting
o Explore practical GenAI use cases for modernization, automation, and platform efficiency




Role:
You will design and build the next-generation Decision Management Platform, the real-time system that scores and approves billions of payment transactions. This is a hands-on role where you will write code, run prototypes, and use AI coding tools every day to ship faster and at higher quality. You will be joining a high-growth team that is actively expanding to meet increasing scale and impact. You will work directly with senior engineers, architects, and product managers to deliver features that make the platform faster, more reliable, and more cost-efficient to run.




Responsibilities:
Develop enterprise applications using a Java technology stack with Angular or React as front-end technologies.
Participate in gathering and refining business requirements.
Ensure software designs align with Client Enterprise Architecture and leverage enterprise services.
Ensure product development meets Client business needs.
Apply Client standard development methodologies, follow technology standards, and ensure projects are appropriately documented.
Ensure software and system design support the goal of zero downtime in production.
Work closely with business partners on product definition, roadmaps, business case development, and overall team direction.
Respond to operational and business concerns related to future programs, projects, or enhancements to ensure consistent delivery of quality services.
Support appropriate certifications and compliance requirements, including PCI, GLBA, Safe Harbor, and others.
Drive performance engineering of the enterprise software architecture and provide guidance, advice, or training to other application developers.
Improve and expand the existing platform by ensuring it is resilient, secure, and scalable.
Use AI tools effectively as part of daily development work, including tools such as Claude Code, Copilot, or similar platforms.