ppSmartCore 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. /p pWe 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. /p h3About the Project: /h3 pYou’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). /p h3What You’ll Do: /h3 ulliDesign and develop new microservices and business logic using Kotlin and Java. /li liOptimize the performance of existing system components and handle high-load areas of the codebase. /li liMake key architectural decisions aimed at improving fault tolerance, scalability, and platform security. /li liIntegrate with third-party payment systems, banks, and processing centers. /li liWork with asynchronous data streams using Kafka and RabbitMQ. /li liConduct code reviews, mentor less experienced colleagues, and promote best development practices. /li liActively participate in RD — exploring and integrating new technologies into the project stack. /li liWrite unit and integration tests to maintain a high-quality codebase. /li /ul h3Our Adecuado Candidate: /h3 ulliHas at least 10 years of commercial backend development experience with Java/Kotlin. /li liDemonstrates expert-level proficiency in Kotlin: understands idioms, coroutines, functional features, and applies them effectively.



/li liPossesses deep knowledge of Java Core and the JVM ecosystem. /li liHas excellent command of Spring Boot — not only building REST APIs but also understanding its internals, auto-configuration, Spring Security, and Actuator. /li liExpert in PostgreSQL — experienced in designing complex data schemas, optimizing queries, understanding transaction isolation levels, and replication mechanisms. /li liExperience with MongoDB. /li liHands‑on experience building systems with Kafka — understanding broker mechanics, producer/consumer patterns, and message delivery guarantees. /li liFamiliar with RabbitMQ and Redis (including caching, pub/sub, and distributed locks). /li liExperience designing and building distributed, fault‑tolerant systems (microservices architecture, CQRS, Event Sourcing). /li liComfortable with modern AI technologies, including AI agents, and capable of applying various LLMs in practice. /li liUnderstanding of networking protocols (TCP/IP, HTTP/2, gRPC). /li liExperience with containerization and orchestration tools (Docker, Kubernetes). /li liWrites clean, maintainable, and well‑tested code. /li liHighly autonomous, proactive, and takes full ownership of product quality and outcomes. /li liFluent in Russian (B2 or higher) — required for daily communication within the team. /li /ul h3Nice to Have: /h3 ulliExperience in fintech or payment processing; familiarity with PCI DSS. /li liExperience with reactive stacks (Project Reactor, WebFlux). /li liFamiliarity with monitoring and tracing tools (Prometheus, Grafana, Jaeger). /li liExperience with load testing tools (JMeter, Gatling). /li /ul h3We Offer: /h3 ulliA competitive salary, discussed individually with each candidate. /li liA modern technology stack and minimal bureaucracy. /li liBudget for training, professional conferences, and books. /li liCorporate access to all top‑tier LLMs with maximum configurations. /li liA team of passionate experts where your voice will always be heard. /li /ul /p #J-18808-Ljbffr

📌 Senior Kotlin/Java (Fintech) – remote friendly (EMEA)
🏢 SMARTCORE
📍 Barcelona