langchain4j
LangChain4j is an idiomatic, open-source Java library for building LLM-powered applications on the JVM. It offers a unified API over popular LLM providers and vector stores, and makes implementing tool calling (including MCP support), agents and RAG easy. It integrates seamlessly with enterprise Java frameworks like Quarkus and Spring Boot.
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LangChain4j is an open-source Java library for building LLM-powered applications on the JVM. It provides a unified API over multiple LLM providers and vector stores, with support for tool calling (including MCP), agents, and RAG.
You want to build LLM applications in Java with one consistent API across providers and vector stores, integrated with Quarkus or Spring Boot.
Use it to
- Build agents with tool calling and MCP support
- Implement RAG pipelines over vector stores
- Swap LLM providers behind a unified API
- Integrate LLM features into Spring Boot or Quarkus apps
- Generate embeddings across multiple providers
For Java and JVM developers building LLM applications
- Role
- agent-framework
- Language
- Java
- Licence
- Apache-2.0
- Forks
- 2,544
- Open issues
- 597
- Last push
- 2026-09-15
- Latest release
- 0.1.0 · 2023-06-20