Senior Java Middleware Engineer – FinTech & Microservices

Okto Payments; Buenos Aires; Hybrid; ARS 136,428,000 - 181,904,000; Full time

Job summary

OKTO is seeking a Java Middleware Engineer to design, develop, and maintain middleware services powering our next-generation payment platform. You will contribute to scalable, secure, high-performance applications that process millions of transactions, collaborating with Product, Architecture, Infrastructure, QA and Security teams.

You will work with Java, Spring Boot, Spring Cloud, OAuth2, and RESTful APIs, building distributed systems and ensuring robust CI/CD.

Qualifications

• Bachelor's degree in Computer Science, Computer Engineering, Software Engineering, IT, or related field.
• 5+ years of professional middleware/backend Java experience.
• At least 1 year with Java 11+.
• Experience in FinTech, Payments, Banking, or Financial Services.
• Strong OOD/SOLID and functional programming understanding.
• Spring Boot and Spring Cloud (Netflix OSS) experience.
• Spring Framework 5 ecosystem knowledge.
• OAuth2 authentication/authorization experience.
• JPA, ORM modeling, persistence experience.
• RESTful API design experience.
• Event-driven architecture and distributed design patterns.
• Git and collaborative workflows.
• Unit testing, clean code, and code review practices.
• Analytical and problem-solving skills.
• Ability to work independently with international teams.
• Technical writing for requirements and designs.

Responsibilities

• Design, develop, and maintain middleware applications and backend services using Java and Spring.
• Develop new features and platform capabilities based on business and technical requirements.
• Build scalable, resilient microservices for payment processing.
• Write clean, maintainable, unit-tested code with performance in mind.
• Participate in distributed systems and event-driven architectures.
• Develop and maintain RESTful APIs and secure integrations with OAuth2.
• Support SIT, UAT, and Production environments for platform stability.
• Collaborate with Product, Architecture, Infrastructure, QA, and Security teams.
• Participate in Agile ceremonies and code reviews.
• Drive continuous improvement in software quality and performance.
• Work with Git and CI/CD pipelines following best practices.
• Produce technical documentation and design specifications.

Skills

Java

Spring Boot

Spring Cloud

RESTful APIs

Microservices

OAuth2

Object-oriented design

Unit testing

Education

Bachelor's degree in Computer Science, Computer Engineering, Software Engineering, IT or related field

Tools

Git

JPA/Hibernate

CI/CD

AWS

Job description

OKTO is seeking a Java Middleware Engineer to design, develop, and maintain middleware services powering our next-generation payment platform. You will contribute to scalable, secure, high-performance applications that process millions of transactions, collaborating with Product, Architecture, Infrastructure, QA and Security teams.

You will work with Java, Spring Boot, Spring Cloud, OAuth2, and RESTful APIs, building distributed systems and ensuring robust CI/CD.