Senior Kotlin/Java Engineer – Fintech, Remote Friendly

About the role

Join SmartCore’s core acquiring platform team to develop and evolve a high‑load, microservices‑based payment processing system that operates 24/7 across the EMEA region. You will work on cutting‑edge fintech solutions, ensuring low latency, fault tolerance, and strict PCI DSS compliance.

Key responsibilities

• Design and implement new microservices and business logic using Kotlin and Java.
• Optimize performance of existing components and address high‑load bottlenecks.
• Make architectural decisions to improve scalability, fault tolerance, and security.
• Integrate with external payment systems, banks, and processing centers.
• Handle asynchronous data streams with Kafka and RabbitMQ.
• Conduct code reviews, mentor junior engineers, and promote best practices.
• Participate in R&D to evaluate and adopt new technologies.
• Write comprehensive unit and integration tests to maintain code quality.

Required profile

• At least 10 years of commercial backend development experience.
• Expert‑level proficiency in Kotlin (coroutines, functional features) and deep knowledge of Java and the JVM.
• Strong command of Spring Boot, including REST APIs, auto‑configuration, security, and actuator.
• Extensive experience with PostgreSQL (complex schemas, query optimization, replication) and MongoDB.
• Hands‑on experience with Kafka, RabbitMQ, and Redis (caching, pub/sub, distributed locks).
• Proven ability to design distributed, fault‑tolerant systems (microservices, CQRS, Event Sourcing).
• Familiarity with modern AI technologies and practical use of LLMs.
• Understanding of networking protocols (TCP/IP, HTTP/2, gRPC).
• Experience with Docker and Kubernetes for containerization and orchestration.
• Fluent Russian (B2 or higher) for daily communication.

Required skills

• Kotlin
• Java
• Spring Boot
• PostgreSQL
• MongoDB
• Kafka
• RabbitMQ
• Redis
• Microservices architecture
• CQRS
• Event Sourcing
• AI / LLM integration
• TCP/IP, HTTP/2, gRPC
• Docker
• Kubernetes