Kotlin/Java Developer

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 Ideal 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 Security, and Actuator. - Expert in PostgreSQL - experienced in designing complex data schemas, optimizing queries, understanding transaction isolation levels, and replication mechanisms. - Experience with MongoDB. - Hands-on experience building systems with Kafka - understanding broker mechanics, producer/consumer patterns, and message delivery guarantees. - Familiar with RabbitMQ and Redis (including caching, pub/sub, and distributed locks). - Experience designing and building distributed, fault-tolerant systems (microservices architecture, CQRS, Event Sourcing). - Comfortable with modern AI technologies, including AI agents, and capable of applying various LLMs in practice. - Understanding of networking protocols (TCP/IP, HTTP/2, gRPC). - Experience with containerization and orchestration tools (Docker, Kubernetes). - Writes clean, maintainable, and well-tested code. - Highly autonomous, proactive, and takes full ownership of product quality and outcomes. - Fluent in Russian (B2 or higher) - required for daily communication within the team. Nice to Have: - Experience in fintech or payment processing; familiarity with PCI DSS. - Experience with reactive stacks (Project Reactor, WebFlux). - Familiarity with monitoring and tracing tools (Prometheus, Grafana, Jaeger). - Experience with load testing tools (JMeter, Gatling). We Offer: - A competitive salary, discussed individually with each candidate. - A modern technology stack and minimal bureaucracy. - Budget for training, professional conferences, and books. - Corporate access to all top-tier LLMs with maximum configurations. - A team of passionate experts where your voice will always be heard. Feel free to apply directly via LinkedIn or by sending your CV to stanislav.pavlov[@]smartcore.pro - if you're ready for serious architectural challenges and want to build a product you can be proud of

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