Onicore is a FinTech company specializing in developing products for cryptocurrency operations. We strive to make crypto convenient and understandable for everyone.
And now we are looking for a talented and experienced Java developer to join our team. If you’re passionate about working with the latest technologies, contributing to exciting product developments, and collaborating with an awesome team, we want to hear from you!
Your Key Duties: * Design, develop, and maintain high-performance, scalable Java-based applications in the FinTech domain. * Implement and optimize multithreaded and concurrent solutions, ensuring thread safety and system reliability. * Build and maintain microservices using the Spring ecosystem. * Ensure database efficiency, including query optimization, proper indexing, and transaction handling. * Evaluate and improve application performance, conduct profiling sessions, and resolve bottlenecks. * Design and implement synchronous and asynchronous integrations with internal and external systems. * Participate in architectural discussions, propose improvements, and drive technical initiatives. * Collaborate closely with product managers, architects, and QA engineers to deliver business-critical solutions. * Write clean, maintainable, and well-tested code following best practices.
Your Skills: * 5+ years of professional experience in Java development. * Strong expertise in Java 17+ (knowledge of modern language features, streams, lambdas, functional programming concepts). * Deep understanding of core Java: * Collections Framework, Generics, Streams, Functional Interfaces * Concurrency utilities (Executors, CompletableFuture, Fork/Join, Locks, Atomics, etc.) * Proven experience with the Spring ecosystem: Spring Boot, Spring Data (JPA/Hibernate), Spring Security, Spring Cloud (microservices). * Solid understanding of databases (SQL and/or NoSQL), including: * Transactions, isolation levels, and locking mechanisms * Query optimization and indexing strategies * Hands-on experience with multithreading and concurrency, including race conditions, deadlocks, synchronization, and strategies to avoid them. * Proficiency in synchronous and asynchronous communication: REST, messaging systems (Kafka, RabbitMQ, etc.), event-driven architectures. * Experience working on FinTech or financial services projects. * Strong focus on performance evaluation, scalability, and reliability. * Strong problem-solving skills, ability to work independently, take initiative, and drive solutions proactively. * Self-driven and responsible, capable of working with minimal supervision. * Proactive, solution-oriented mindset. * Team player with a collaborative attitude.
Nice to have: * Experience with Kubernetes, Docker, and cloud-native environments. * Experience with application profiling and performance tuning: * Tools such as VisualVM, JFR (Java Flight Recorder), JMC (Java Mission Control) * Identifying and resolving performance bottlenecks * Analyzing complexity of SQL queries and optimizing execution plans * Familiarity with CI/CD pipelines and DevOps practices. * Knowledge of distributed systems, event sourcing, or CQRS.
What’s on us:
— Competitive salary and benefits package.
— Opportunities for professional development and career growth.
— Health insurance.
— Remote work with the possibility to visit our office in Kyiv.
— Space to share your ideas and bring them to life.
