Mid-Senior Java Software Engineer (Remote - Argentina) - ARG112-DV

OKTO's continuous growth demands high-caliber candidates who embody professionalism, passion, and creativity. For those who join us, we offer significant career advancement, stimulating challenges, and a clear runway for growth.

OKTO is the next-generation Payment Service Provider — AI-native, precision-engineered, and relentlessly merchant-obsessed. Built for merchants operating in the most complex and demanding eCommerce sectors, our platform goes far beyond transaction processing. We solve for scale, compliance, and performance with one unshakable focus: delivering outcomes that power merchant growth.

From payments and banking to treasury and settlement, we engineer the financial infrastructure that gives our partners a competitive edge. The result? Faster onboarding, smarter operations, and resilient, real-time performance.

At OKTO, we enable merchants to Play Differently, transforming payments from routine transactions into true differentiators that deliver personalized, frictionless experiences.

Our AI-native innovation harnesses data and insight to power every decision, while our proprietary in-house engineering ensures precision and control. Combined with deep, trust-based relationships worldwide, we're redefining what it means to build, scale, and win in complex digital commerce.

Summary

As a Java Middleware Engineer , you will play a key role in designing, developing, and maintaining the middleware services that power our next-generation payment platform. You will contribute to the development of scalable, secure, and high-performance applications that process millions of financial transactions, while collaborating with Product, Architecture, Infrastructure, QA, and Security teams.

Key Responsibilities

• Design, develop, and maintain middleware applications and backend services using Java and Spring technologies

• Develop new product features and platform capabilities based on business and technical requirements

• Build scalable, resilient, and high-performance microservices that support payment processing and financial transaction workflows

• Write clean, maintainable, and performance-optimized code, ensuring high-quality standards and comprehensive unit test coverage

• Participate in the design and implementation of distributed systems and event-driven architectures

• Develop and maintain RESTful APIs and secure service integrations using modern authentication mechanisms such as OAuth2

• Support System Integration Testing (SIT), User Acceptance Testing (UAT), and Production environments, identifying and resolving issues to ensure platform stability

• Collaborate with cross-functional teams, including Product Managers, QA Engineers, DevOps Engineers, and Solution Architects, to deliver high-quality software solutions

• Participate in Agile ceremonies, code reviews, technical discussions, and knowledge-sharing initiatives

• Contribute to continuous improvement by identifying opportunities to optimize software quality, development processes, and system performance

• Work with version control systems and CI/CD pipelines, following engineering best practices and software development standards

• Produce technical documentation, including product specifications, design documentation, and implementation details

Requirements

• Bachelor's degree in Computer Science, Computer Engineering, Software Engineering, Information Technology, or a related field

• Minimum of 5 years of professional experience developing middleware or backend applications using Java

• At least 1 year of hands-on experience with Java 11 or newer

• Proven experience working within the FinTech, Payments, Banking, or Financial Services industry

• Strong understanding of Object-Oriented Design (OOD), SOLID principles, and Functional Programming concepts

• Experience designing and developing microservices architectures using Spring Boot and Spring Cloud (Netflix OSS)

• Solid knowledge of the Spring Framework 5 ecosystem

• Experience implementing secure authentication and authorization using OAuth2

• Experience with JPA, ORM modeling, and persistence frameworks

• Strong experience designing and developing RESTful APIs

• Familiarity with Event-Driven Architecture, asynchronous messaging, and distributed software design patterns

• Experience working with Git and collaborative source control workflows

• Good understanding of software development best practices, including unit testing, clean code principles, and code review processes

• Strong analytical, problem-solving, and troubleshooting skills

• Ability to work independently while collaborating effectively within an international engineering team

• Excellent technical writing skills for documenting requirements, software designs, and technical specifications

Preferred Qualifications

• Experience with cloud platforms such as AWS

• Familiarity with CI/CD pipelines and DevOps practices

• Experience working in high-volume transaction processing environments

• Knowledge of payment processing concepts, transaction lifecycle, settlement, reconciliation, or payment gateway integrations

• Experience with monitoring, logging, and application performance optimization

Languages

• Advanced English (mandatory), with the ability to participate in technical discussions, collaborate with international teams, and produce technical documentation

• Spanish (mandatory)

Please submit your resumé in English.

Benefits

• Competitive Compensation - Competitive salary package

• Career Growth - Career development opportunities in a growing global fintech

• Continuous Learning - Access to challenging projects and continuous learning opportunities

• Inclusive Environment - Collaborative, diverse, and international work environment

• Birthday Leave - Paid day off on your birthday