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 Securit

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