Ivan R.

Senior Java Developer | Backend, API Integrations, System Design, AI

I help companies build and improve Java backend systems, API integrations, and scalable product architecture. With 13+ years of experience, I work with startups and established companies on backend development, third-party integrations, architecture decisions, and long-term product improvement. I’m a good fit if you need to: - build or extend a Java backend application - integrate external APIs, payment providers, or third-party services - improve architecture in an existing product - optimize performance, reliability, and database queries - estimate technical scope before development starts - AI features such as RAG, vector search, or LLM integrations to an existing backend Core stack: - Java, Kotlin - Spring Boot, Spring MVC, Spring Security, Spring Data, Hibernate, JPA, jOOQ - PostgreSQL, MySQL, MongoDB, Oracle REST APIs, SOAP, backend integrations - GitLab, Bitbucket, Jenkins, Fastlane I also work with AI backend integrations, including Spring AI, MCP servers and tools, OpenAI/Groq/OpenRouter integrations, embeddings, vector databases, and RAG architecture. Feel free to message me if you need a backend architecture review, API integration estimate, or help with improving an existing Java product.