About the Company:SmartCore is a fintech holding building infrastructure for the next generation of payments. Our solutions cover the entire financial operations cycle — from core banking and processing to cards, wallets, and anti-fraud systems.We are a leading fintech company developing innovative solutions in payment processing and anti-fraud technologies. We create high-tech products that are reshaping the financial landscape and are looking for true professionals ready to tackle complex and ambitious challenges.About the Project:You'll join a key team responsible for developing and evolving our core acquiring platform — a complex, high-load, microservices-based system operating 24/7. We handle the entire payment lifecycle, from initiation to clearing, ensuring minimal latency, high fault tolerance,



and full compliance with strict security standards (PCI DSS).What You'll Do:Design and develop new microservices and business logic using Kotlin and Java.Optimize the performance of existing system components and handle high-load areas of the codebase.Make key architectural decisions aimed at improving fault tolerance, scalability, and platform security.Integrate with third-party payment systems, banks, and processing centers.Work with asynchronous data streams using Kafka and RabbitMQ.Conduct code reviews, mentor less experienced colleagues, and promote best development practices.Actively participate in R&D; — exploring and integrating new technologies into the project stack.Write unit and integration tests to maintain a high-quality codebase.Our Idóneo Candidate:Has at least 10 years of commercial backend development experience with Java/Kotlin.Demonstrates expert-level proficiency in Kotlin: understands idioms, coroutines, functional features, and applies them effectively.Possesses deep knowledge of Java Core and the JVM ecosystem.Has excellent command of Spring Boot — not only building REST APIs but also understanding its internals, auto-configuration, Spring Securi

📌 Senior Kotlin/Java (España)
🏢 SMARTCORE
📍 España