What it does
LangChain4j is a code library for the Java world that helps programmers add AI language models to their software. It offers one common way to talk to many different AI providers and data stores.
It includes ready-made pieces for common tasks, such as giving an AI access to tools, building chatbots, and letting an AI answer questions from your own documents.
Its makers note that, despite the name, it is not a copy of the Python LangChain project but is built for Java.
Who it's for
Java developers who want to build AI features into their applications.
Can I use it without coding?
Developers only. It is a code library for programmers, used inside Java projects. New to this? Start here.
Can I run it?
- Cost
- Free, but needs an AI accountThe software is free, but it uses an online AI service (like OpenAI or Anthropic), which usually charges for use.
- Runs on
- Server
- Computer
- An ordinary computer is fine
- Privacy
- Your choice: run it on your device or use an online service
- API key
- Needed. An API key is a password-like code from an online AI service. What's that?
Try it
Using Claude Code, Cursor or another AI coding assistant? Paste the prompt and it will walk you through the setup.New to this?
Before you install
- Only download from the official GitHub page. Copies with similar names exist for many popular projects.
- License (Apache-2.0): Permissive: free to use, change and share, including for business.
- Keep your API key private. Never paste it into websites or share it, and set a spending limit with the AI service.
- More on staying safe