Get Started

note

If you are using Quarkus, see Quarkus Integration.

If you are using Spring Boot, see Spring Boot Integration.

LangChain4j offers integration with many LLM providers. Each integration has its own maven dependency. The simplest way to begin is with the OpenAI integration:

• For Maven in pom.xml:

<dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j-open-ai</artifactId>
    <version>0.36.2</version>
</dependency>

If you wish to use a high-level AI Services API, you will also need to add the following dependency:

<dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j</artifactId>
    <version>0.36.2</version>
</dependency>

• For Gradle in build.gradle:

implementation 'dev.langchain4j:langchain4j-open-ai:0.36.2'
implementation 'dev.langchain4j:langchain4j:0.36.2'

Bill of Materials (BOM)

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-bom</artifactId>
            <version>0.36.2</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

SNAPSHOT dependencies (newest features)

If you'd like to test the newest features before their official release, you can use the most recent SNAPSHOT dependency:

<repositories>
    <repository>
        <id>snapshots-repo</id>
        <url>https://s01.oss.sonatype.org/content/repositories/snapshots</url>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>dev.langchain4j</groupId>
        <artifactId>langchain4j</artifactId>
        <version>0.37.0-SNAPSHOT</version>
    </dependency>
</dependencies>

Then, import your OpenAI API key. It's recommended to store your API keys in environment variables to reduce the risk of exposing them publicly.

String apiKey = System.getenv("OPENAI_API_KEY");

note

If you don't have your own OpenAI API key, don't worry. You can temporarily use demo key, which we provide for free for demonstration purposes:

String apiKey = "demo";

Be aware that when using the demo key, all requests to the OpenAI API go through our proxy, which injects the real key before forwarding your request to the OpenAI API. We do not collect or use your data in any way. The demo key has a quota, is restricted to the gpt-4o-mini model, and should only be used for demonstration purposes.

Once you've set up the key, let's create an instance of an OpenAiChatModel:

OpenAiChatModel model = OpenAiChatModel.builder()
    .apiKey(apiKey)
    .modelName(GPT_4_O_MINI)
    .build();

Now, it is time to chat!

String answer = model.generate("Say 'Hello World'");
System.out.println(answer); // Hello World