# LangChain4j

> LangChain4j is a Java library providing vector search and embedding capabilities for LLM applications via integrations with ANN indexes like HNSW and FAISS, without needing full vector databases. Features include support for quantization, tool calling, and seamless embedding in JVM environments like Spring Boot and Quarkus. Suited for prototyping RAG agents and embedded apps; lighter and more JVM-native than Milvus, easier integration vs hnswlib.

- **URL:** https://langchain4j.dev/
- **Category:** Libraries
- **Tags:** Open Source, Java, Rag, Ann Library, Embeddable
- **Updated:** 2026-04-24 10:19
- **Canonical page:** https://vectordb.ever.works/items/langchain4j

## Details

## Overview

LangChain4j is an idiomatic, open-source Java library for building LLM-powered applications on the JVM.

## Features

- Unified API over popular LLM providers and vector stores
- Easy implementation of tool calling (including MCP support), agents, and RAG
- Seamless integration with enterprise Java frameworks like Quarkus and Spring Boot

## Pricing

Free and open-source.

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