Senior Java Developer (LLM / LangChain / AWS / Prompt Engineering)

Senior Java Developer (LLM / LangChain / AWS / Prompt Engineering) – Remote / Europe

Who we’re looking for:
An experienced Senior Java Developer who has worked with LLM integrations, especially using LangChain for Java, and is excited about building cutting-edge AI-powered applications. You will help us integrate models like Claude (Anthropic), Mistral, and OpenAI into our backend products, with a strong focus on API design, prompt engineering, and performance.

Location: EU, Ukraine
Remote, Fulltime, Longterm

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Tech Stack

• Java 11–17, Spring Boot, REST APIs
• LangChain4j (LangChain for Java), PromptTemplate, ChainBuilder
• LLMs: Claude (Anthropic), Mistral, OpenAI
• Prompt Engineering: few-shot, zero-shot, tool calling, safety best practices
• AWS: Lambda, SQS, SNS, VPC, Secrets Manager
• Bonus: Kotlin, Kubernetes, Redis (for memory), embedding stores (e.g. Pinecone, pgvector)

Requirements
• 5+ years of experience with Java in production
• 1+ year of hands-on work with LLM integrations (LangChain or custom)
• Strong understanding of Prompt Engineering
• Experience with AWS cloud infrastructure
• Able to communicate in English (Upper-Intermediate or better)
• Based in Europe (or nearby time zones)
• Bonus: worked on AI agents / copilots / chatbots