OneMain Financial Jobs

Job Description

We are looking for a Senior API Developer with a strong Java technology stack and proven experience designing and building APIs from scratch. This role will focus on developing high performance, scalable, and secure APIs that support critical business applications and event-driven architectures.

You will work closely with architects, product teams, and downstream consumers to define API contracts, implement services, and ensure reliability at scale.

Key Responsibilities

• Design, develop, and maintain RESTful and event-driven APIs using Java

• Build greenfield APIs from the ground up, including design, implementation, testing, and deployment

• Develop and integrate Kafka-based messaging solutions for asynchronous and event-driven communication

• Define API standards, contracts, versioning strategies, and documentation

• Ensure APIs meet performance, scalability, and security requirements

• Implement robust error handling, logging, monitoring, and observability

• Collaborate with cross-functional teams to translate business requirements into technical API solutions

• Participate in architectural discussions and contribute to system design decisions

• Support API lifecycle management, including enhancements, refactoring, and deprecation

• Ensure high code quality through code reviews, automated testing, and best practices

We are a company committed to creating diverse and inclusive environments where people can bring their full, authentic selves to work every day. We are an equal opportunity/affirmative action employer that believes everyone matters. Qualified candidates will receive consideration for employment regardless of their race, color, ethnicity, religion, sex (including pregnancy), sexual orientation, gender identity and expression, marital status, national origin, ancestry, genetic factors, age, disability, protected veteran status, military or uniformed service member status, or any other status or characteristic protected by applicable laws, regulations, and ordinances. If you need assistance and/or a reasonable accommodation due to a disability during the application or recruiting process, please send a request to HR@insightglobal.com.To learn more about how we collect, keep, and process your private information, please review Insight Global's Workforce Privacy Policy: https://insightglobal.com/workforce-privacy-policy/.

Skills and Requirements

• 8+ years of professional software development experience

• Strong expertise in Java and the Java ecosystem

• Proven experience building APIs from scratch (RESTful services, microservices)

• Hands-on experience with Apache Kafka (producers, consumers, topic design, message handling)

• Strong understanding of microservices architecture

• Experience with API security concepts (authentication, authorization, tokens, etc.)

• Experience with Git and modern source control workflows

• Solid understanding of software design principles and patterns

• Strong debugging, problem-solving, and performance-tuning skills

• Experience with Spring / Spring Boot

• Familiarity with containerization and deployment (Docker, Kubernetes)

• Experience working in cloud environments (Azure, AWS, or GCP)

• Experience with CI/CD pipelines and DevOps practices

• Knowledge of API gateways and service meshes

• Experience working in enterprise or high-availability systems