Senior Java Developer

📍 Warsaw (Onsite – near Metro Plac Wilsona) 💼 B2B / Freelance About Silk Software House Silk Software House builds and maintains mission-critical backend systems for fintech, payments, and large-scale platforms. We value strong engineering judgment, ownership, and long-term cooperation over short-term delivery pressure. Your Role As a Senior Java Developer, you’ll take technical ownership of backend services, influence architectural decisions, and mentor other engineers. You’ll work directly on complex domains where performance, security, and reliability matter. Responsibilities • Design and implement backend architectures using Java 11+ and Spring • Lead development of microservices and APIs • Optimize performance, scalability, and data consistency • Work deeply with Hibernate, transactions, and database internals • Review code, mentor developers, and set engineering standards • Collaborate with DevOps on deployments and observability Requirements • This role requires full-time onsite work (no remote or hybrid options). Candidates must be willing and able to work from our office near the Plac Wilsona metro station • 5+ years of commercial experience as a Java Developer • Strong commercial experience with Java & Spring (Boot, Security, Data) • Deep knowledge of Hibernate ORM, SQL databases, and JVM behavior • Experience designing scalable, maintainable backend architectures • Proficiency with CI/CD, Git, Gradle, and production debugging • Effective use of AI-assisted development tools (ChatGPT, Claude, Cursor, Grok) • English at B2+ level Nice to Have • Event-driven architecture (Kafka, queues) • Cloud-native systems (AWS/GCP/Azure) • Kubernetes, Docker, observability tools • Experience in fintech or high-traffic systems Rates (B2B) • 120–160 PLN / hour Recruitment Process • Intro call (30 min) • Senior-level technical interview • Architecture & project discussion • Offer Tech Stack • Java: Advanced • Spring Boot: Advanced • Hibernate: Advanced • PostgreSQL: Advanced • Solid: Advanced • DDD: Advanced • REST API: Advanced