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README 

          
# Anthropic Java API Library



[![Maven Central](https://img.shields.io/maven-central/v/com.anthropic/anthropic-java)](https://central.sonatype.com/artifact/com.anthropic/anthropic-java/2.1.0)

[![javadoc](https://javadoc.io/badge2/com.anthropic/anthropic-java/2.1.0/javadoc.svg)](https://javadoc.io/doc/com.anthropic/anthropic-java/2.1.0)



The Anthropic Java SDK provides convenient access to the [Anthropic REST API](https://docs.anthropic.com/claude/reference/) from applications written in Java.



The REST API documentation can be found on [docs.anthropic.com](https://docs.anthropic.com/claude/reference/). Javadocs are available on [javadoc.io](https://javadoc.io/doc/com.anthropic/anthropic-java/2.1.0).



## Installation



### Gradle



```kotlin

implementation("com.anthropic:anthropic-java:2.1.0")

```



### Maven



```xml



  com.anthropic

  anthropic-java

  2.1.0



```



## Requirements



This library requires Java 8 or later.



## Usage



See the [`anthropic-java-example`](anthropic-java-example/src/main/java/com/anthropic/example) directory for complete and runnable examples.



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import com.anthropic.models.messages.Message;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;



// Configures using the `ANTHROPIC_API_KEY`, `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_BASE_URL` environment variables

AnthropicClient client = AnthropicOkHttpClient.fromEnv();



MessageCreateParams params = MessageCreateParams.builder()

    .maxTokens(1024L)

    .addUserMessage("Hello, Claude")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .build();

Message message = client.messages().create(params);

```



## Client configuration



Configure the client using environment variables:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



// Configures using the `ANTHROPIC_API_KEY`, `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_BASE_URL` environment variables

AnthropicClient client = AnthropicOkHttpClient.fromEnv();

```



Or manually:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .apiKey("my-anthropic-api-key")

    .build();

```



Or using a combination of the two approaches:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



AnthropicClient client = AnthropicOkHttpClient.builder()

    // Configures using the `ANTHROPIC_API_KEY`, `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_BASE_URL` environment variables

    .fromEnv()

    .apiKey("my-anthropic-api-key")

    .build();

```



See this table for the available options:



| Setter      | Environment variable   | Required | Default value                 |

| ----------- | ---------------------- | -------- | ----------------------------- |

| `apiKey`    | `ANTHROPIC_API_KEY`    | false    | -                             |

| `authToken` | `ANTHROPIC_AUTH_TOKEN` | false    | -                             |

| `baseUrl`   | `ANTHROPIC_BASE_URL`   | true     | `"https://api.anthropic.com"` |



> [!TIP]

> Don't create more than one client in the same application. Each client has a connection pool and

> thread pools, which are more efficient to share between requests.



## Requests and responses



To send a request to the Anthropic API, build an instance of some `Params` class and pass it to the corresponding client method. When the response is received, it will be deserialized into an instance of a Java class.



For example, `client.messages().create(...)` should be called with an instance of `MessageCreateParams`, and it will return an instance of `Message`.



### Long requests



> [!IMPORTANT]  

> We highly encourage you to use [streaming](#streaming) for longer running requests.



We do not recommend setting a large `maxTokens` value without using streaming. Some networks may drop idle connections after a certain period of time, which can cause the request to fail or [timeout](#timeouts) without receiving a response from Anthropic. We periodically ping the API to keep the connection alive and reduce the impact of these networks.



The SDK throws an error if a non-streaming request is expected to take longer than 10 minutes. Using a [streaming method](#streaming) or [overriding the timeout](#timeouts) at the client or request level disables the error.



## Immutability



Each class in the SDK has an associated [builder](https://blogs.oracle.com/javamagazine/post/exploring-joshua-blochs-builder-design-pattern-in-java) or factory method for constructing it.



Each class is [immutable](https://docs.oracle.com/javase/tutorial/essential/concurrency/immutable.html) once constructed. If the class has an associated builder, then it has a `toBuilder()` method, which can be used to convert it back to a builder for making a modified copy.



Because each class is immutable, builder modification will _never_ affect already built class instances.



## Asynchronous execution



The default client is synchronous. To switch to asynchronous execution, call the `async()` method:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import com.anthropic.models.messages.Message;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;

import java.util.concurrent.CompletableFuture;



// Configures using the `ANTHROPIC_API_KEY`, `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_BASE_URL` environment variables

AnthropicClient client = AnthropicOkHttpClient.fromEnv();



MessageCreateParams params = MessageCreateParams.builder()

    .maxTokens(1024L)

    .addUserMessage("Hello, Claude")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .build();

CompletableFuture message = client.async().messages().create(params);

```



Or create an asynchronous client from the beginning:



```java

import com.anthropic.client.AnthropicClientAsync;

import com.anthropic.client.okhttp.AnthropicOkHttpClientAsync;

import com.anthropic.models.messages.Message;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;

import java.util.concurrent.CompletableFuture;



// Configures using the `ANTHROPIC_API_KEY`, `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_BASE_URL` environment variables

AnthropicClientAsync client = AnthropicOkHttpClientAsync.fromEnv();



MessageCreateParams params = MessageCreateParams.builder()

    .maxTokens(1024L)

    .addUserMessage("Hello, Claude")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .build();

CompletableFuture message = client.messages().create(params);

```



The asynchronous client supports the same options as the synchronous one, except most methods return `CompletableFuture`s.



## Streaming



The SDK defines methods that return response "chunk" streams, where each chunk can be individually processed as soon as it arrives instead of waiting on the full response. Streaming methods generally correspond to [SSE](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events) or [JSONL](https://jsonlines.org) responses.



Some of these methods may have streaming and non-streaming variants, but a streaming method will always have a `Streaming` suffix in its name, even if it doesn't have a non-streaming variant.



These streaming methods return [`StreamResponse`](anthropic-java-core/src/main/kotlin/com/anthropic/core/http/StreamResponse.kt) for synchronous clients:



```java

import com.anthropic.core.http.StreamResponse;

import com.anthropic.models.messages.RawMessageStreamEvent;



try (StreamResponse streamResponse = client.messages().createStreaming(params)) {

    streamResponse.stream().forEach(chunk -> {

        System.out.println(chunk);

    });

    System.out.println("No more chunks!");

}

```



Or [`AsyncStreamResponse`](anthropic-java-core/src/main/kotlin/com/anthropic/core/http/AsyncStreamResponse.kt) for asynchronous clients:



```java

import com.anthropic.core.http.AsyncStreamResponse;

import com.anthropic.models.messages.RawMessageStreamEvent;

import java.util.Optional;



client.async().messages().createStreaming(params).subscribe(chunk -> {

    System.out.println(chunk);

});



// If you need to handle errors or completion of the stream

client.async().messages().createStreaming(params).subscribe(new AsyncStreamResponse.Handler<>() {

    @Override

    public void onNext(RawMessageStreamEvent chunk) {

        System.out.println(chunk);

    }



    @Override

    public void onComplete(Optional error) {

        if (error.isPresent()) {

            System.out.println("Something went wrong!");

            throw new RuntimeException(error.get());

        } else {

            System.out.println("No more chunks!");

        }

    }

});



// Or use futures

client.async().messages().createStreaming(params)

    .subscribe(chunk -> {

        System.out.println(chunk);

    })

    .onCompleteFuture();

    .whenComplete((unused, error) -> {

        if (error != null) {

            System.out.println("Something went wrong!");

            throw new RuntimeException(error);

        } else {

            System.out.println("No more chunks!");

        }

    });

```



Async streaming uses a dedicated per-client cached thread pool [`Executor`](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/Executor.html) to stream without blocking the current thread. This default is suitable for most purposes.



To use a different `Executor`, configure the subscription using the `executor` parameter:



```java

import java.util.concurrent.Executor;

import java.util.concurrent.Executors;



Executor executor = Executors.newFixedThreadPool(4);

client.async().messages().createStreaming(params).subscribe(

    chunk -> System.out.println(chunk), executor

);

```



Or configure the client globally using the `streamHandlerExecutor` method:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import java.util.concurrent.Executors;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .fromEnv()

    .streamHandlerExecutor(Executors.newFixedThreadPool(4))

    .build();

```



### Streaming helpers



The SDK provides conveniences for streamed messages. A

[`MessageAccumulator`](anthropic-java-core/src/main/kotlin/com/anthropic/helpers/MessageAccumulator.kt)

can record the stream of events in the response as they are processed and accumulate a

[`Message`](anthropic-java-core/src/main/kotlin/com/anthropic/models/messages/Message.kt) object

similar to that which would have been returned by the non-streaming API.



A [`BetaMessageAccumulator`](anthropic-java-core/src/main/kotlin/com/anthropic/helpers/BetaMessageAccumulator.kt)

is also available for the accumulation of a

[`BetaMessage`](anthropic-java-core/src/main/kotlin/com/anthropic/models/beta/messages/BetaMessage.kt)

object. It is used in the same manner as the `MessageAccumulator`.



For a synchronous response add a

[`Stream.peek()`](https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#peek-java.util.function.Consumer-)

call to the stream pipeline to accumulate each event:



```java

import com.anthropic.core.http.StreamResponse;

import com.anthropic.helpers.MessageAccumulator;

import com.anthropic.models.messages.Message;

import com.anthropic.models.messages.RawMessageStreamEvent;



MessageAccumulator messageAccumulator = MessageAccumulator.create();



try (StreamResponse streamResponse =

         client.messages().createStreaming(createParams)) {

    streamResponse.stream()

            .peek(messageAccumulator::accumulate)

            .flatMap(event -> event.contentBlockDelta().stream())

            .flatMap(deltaEvent -> deltaEvent.delta().text().stream())

            .forEach(textDelta -> System.out.print(textDelta.text()));

}



Message message = messageAccumulator.message();

```



For an asynchronous response, add the `MessageAccumulator` to the `subscribe()` call:



```java

import com.anthropic.helpers.MessageAccumulator;

import com.anthropic.models.messages.Message;



MessageAccumulator messageAccumulator = MessageAccumulator.create();



client.messages()

        .createStreaming(createParams)

        .subscribe(event -> messageAccumulator.accumulate(event).contentBlockDelta().stream()

                .flatMap(deltaEvent -> deltaEvent.delta().text().stream())

                .forEach(textDelta -> System.out.print(textDelta.text())))

        .onCompleteFuture()

        .join();



Message message = messageAccumulator.message();

```



## File uploads



The SDK defines methods that accept files, the main interface for which is exposed through [`MultipartField`](anthropic-java-core/src/main/kotlin/com/anthropic/core/Values.kt):



```java

import com.anthropic.core.MultipartField;

import com.anthropic.models.beta.files.FileMetadata;

import com.anthropic.models.beta.files.FileUploadParams;

import com.anthropic.models.beta.AnthropicBeta;

import java.nio.file.Paths;



FileUploadParams params = FileUploadParams.builder()

    .file(MultipartField.builder()

        .value(Paths.get("/path/to/file.pdf"))

        .contentType("application/pdf") // content type must be manually specified

        .build())

    .addBeta(AnthropicBeta.FILES_API_2025_04_14)

    .build();

FileMetadata fileMetadata = client.beta().files().upload(params);

```



Or an arbitrary [`InputStream`](https://docs.oracle.com/javase/8/docs/api/java/io/InputStream.html):



```java

import com.anthropic.core.MultipartField;

import com.anthropic.models.beta.files.FileMetadata;

import com.anthropic.models.beta.files.FileUploadParams;

import com.anthropic.models.beta.AnthropicBeta;

import java.io.InputStream;

import java.net.URL;



FileUploadParams params = FileUploadParams.builder()

    .file(MultipartField.builder()

        .value(new URL("https://example.com/path/to/file").openStream())

        .filename("document.pdf")

        .contentType("application/pdf")

        .build())

    .addBeta(AnthropicBeta.FILES_API_2025_04_14)

    .build();

FileMetadata fileMetadata = client.beta().files().upload(params);

```



Or a `byte[]` array:



```java

import com.anthropic.core.MultipartField;

import com.anthropic.models.beta.files.FileMetadata;

import com.anthropic.models.beta.files.FileUploadParams;

import com.anthropic.models.beta.AnthropicBeta;



FileUploadParams params = FileUploadParams.builder()

    .file(MultipartField.builder()

        .value("content".getBytes())

        .filename("document.txt")

        .contentType("text/plain")

        .build())

    .addBeta(AnthropicBeta.FILES_API_2025_04_14)

    .build();

FileMetadata fileMetadata = client.beta().files().upload(params);

```



Note that you can also pass certain values directly, however this is not recommended as the

files API will not infer the correct content-type for you.



```java

FileUploadParams params = FileUploadParams.builder()

    .file(Paths.get("/path/to/file"))

    .addBeta(AnthropicBeta.FILES_API_2025_04_14)

    .build();

```



## Binary responses



The SDK defines methods that return binary responses, which are used for API responses that shouldn't necessarily be parsed, like non-JSON data.



These methods return [`HttpResponse`](anthropic-java-core/src/main/kotlin/com/anthropic/core/http/HttpResponse.kt):



```java

import com.anthropic.core.http.HttpResponse;

import com.anthropic.models.beta.files.FileDownloadParams;



HttpResponse response = client.beta().files().download("file_id");

```



To save the response content to a file, use the [`Files.copy(...)`](https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#copy-java.io.InputStream-java.nio.file.Path-java.nio.file.CopyOption...-) method:



```java

import com.anthropic.core.http.HttpResponse;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.nio.file.StandardCopyOption;



try (HttpResponse response = client.beta().files().download(params)) {

    Files.copy(

        response.body(),

        Paths.get(path),

        StandardCopyOption.REPLACE_EXISTING

    );

} catch (Exception e) {

    System.out.println("Something went wrong!");

    throw new RuntimeException(e);

}

```



Or transfer the response content to any [`OutputStream`](https://docs.oracle.com/javase/8/docs/api/java/io/OutputStream.html):



```java

import com.anthropic.core.http.HttpResponse;

import java.nio.file.Files;

import java.nio.file.Paths;



try (HttpResponse response = client.beta().files().download(params)) {

    response.body().transferTo(Files.newOutputStream(Paths.get(path)));

} catch (Exception e) {

    System.out.println("Something went wrong!");

    throw new RuntimeException(e);

}

```



## Raw responses



The SDK defines methods that deserialize responses into instances of Java classes. However, these methods don't provide access to the response headers, status code, or the raw response body.



To access this data, prefix any HTTP method call on a client or service with `withRawResponse()`:



```java

import com.anthropic.core.http.Headers;

import com.anthropic.core.http.HttpResponseFor;

import com.anthropic.models.messages.Message;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;



MessageCreateParams params = MessageCreateParams.builder()

    .maxTokens(1024L)

    .addUserMessage("Hello, Claude")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .build();

HttpResponseFor message = client.messages().withRawResponse().create(params);



int statusCode = message.statusCode();

Headers headers = message.headers();

```



You can still deserialize the response into an instance of a Java class if needed:



```java

import com.anthropic.models.messages.Message;



Message parsedMessage = message.parse();

```



### Request IDs



> For more information on debugging requests, see [the API docs](https://docs.anthropic.com/en/api/errors#request-id).



When using raw responses, you can access the `request-id` response header using the `requestId()` method:



```java

import com.anthropic.core.http.HttpResponseFor;

import com.anthropic.models.messages.Message;

import java.util.Optional;



HttpResponseFor message = client.messages().withRawResponse().create(params);

Optional requestId = message.requestId();

```



This can be used to quickly log failing requests and report them back to Anthropic.



## Error handling



The SDK throws custom unchecked exception types:



- [`AnthropicServiceException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/AnthropicServiceException.kt): Base class for HTTP errors. See this table for which exception subclass is thrown for each HTTP status code:



  | Status | Exception                                                                                                                    |

  | ------ | ---------------------------------------------------------------------------------------------------------------------------- |

  | 400    | [`BadRequestException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/BadRequestException.kt)                     |

  | 401    | [`UnauthorizedException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/UnauthorizedException.kt)                 |

  | 403    | [`PermissionDeniedException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/PermissionDeniedException.kt)         |

  | 404    | [`NotFoundException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/NotFoundException.kt)                         |

  | 422    | [`UnprocessableEntityException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/UnprocessableEntityException.kt)   |

  | 429    | [`RateLimitException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/RateLimitException.kt)                       |

  | 5xx    | [`InternalServerException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/InternalServerException.kt)             |

  | others | [`UnexpectedStatusCodeException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/UnexpectedStatusCodeException.kt) |



  [`SseException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/SseException.kt) is thrown for errors encountered during [SSE streaming](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events) after a successful initial HTTP response.



- [`AnthropicIoException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/AnthropicIoException.kt): I/O networking errors.



- [`AnthropicInvalidDataException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/AnthropicInvalidDataException.kt): Failure to interpret successfully parsed data. For example, when accessing a property that's supposed to be required, but the API unexpectedly omitted it from the response.



- [`AnthropicException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/AnthropicException.kt): Base class for all exceptions. Most errors will result in one of the previously mentioned ones, but completely generic errors may be thrown using the base class.



## Pagination



The SDK defines methods that return a paginated lists of results. It provides convenient ways to access the results either one page at a time or item-by-item across all pages.



### Auto-pagination



To iterate through all results across all pages, use the `autoPager()` method, which automatically fetches more pages as needed.



When using the synchronous client, the method returns an [`Iterable`](https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html)



```java

import com.anthropic.models.beta.messages.batches.BatchListPage;

import com.anthropic.models.beta.messages.batches.BetaMessageBatch;



BatchListPage page = client.beta().messages().batches().list();



// Process as an Iterable

for (BetaMessageBatch batch : page.autoPager()) {

    System.out.println(batch);

}



// Process as a Stream

page.autoPager()

    .stream()

    .limit(50)

    .forEach(batch -> System.out.println(batch));

```



When using the asynchronous client, the method returns an [`AsyncStreamResponse`](anthropic-java-core/src/main/kotlin/com/anthropic/core/http/AsyncStreamResponse.kt):



```java

import com.anthropic.core.http.AsyncStreamResponse;

import com.anthropic.models.beta.messages.batches.BatchListPageAsync;

import com.anthropic.models.beta.messages.batches.BetaMessageBatch;

import java.util.Optional;

import java.util.concurrent.CompletableFuture;



CompletableFuture pageFuture = client.async().beta().messages().batches().list();



pageFuture.thenRun(page -> page.autoPager().subscribe(batch -> {

    System.out.println(batch);

}));



// If you need to handle errors or completion of the stream

pageFuture.thenRun(page -> page.autoPager().subscribe(new AsyncStreamResponse.Handler<>() {

    @Override

    public void onNext(BetaMessageBatch batch) {

        System.out.println(batch);

    }



    @Override

    public void onComplete(Optional error) {

        if (error.isPresent()) {

            System.out.println("Something went wrong!");

            throw new RuntimeException(error.get());

        } else {

            System.out.println("No more!");

        }

    }

}));



// Or use futures

pageFuture.thenRun(page -> page.autoPager()

    .subscribe(batch -> {

        System.out.println(batch);

    })

    .onCompleteFuture()

    .whenComplete((unused, error) -> {

        if (error != null) {

            System.out.println("Something went wrong!");

            throw new RuntimeException(error);

        } else {

            System.out.println("No more!");

        }

    }));

```



### Manual pagination



To access individual page items and manually request the next page, use the `items()`,

`hasNextPage()`, and `nextPage()` methods:



```java

import com.anthropic.models.beta.messages.batches.BatchListPage;

import com.anthropic.models.beta.messages.batches.BetaMessageBatch;



BatchListPage page = client.beta().messages().batches().list();

while (true) {

    for (BetaMessageBatch batch : page.items()) {

        System.out.println(batch);

    }



    if (!page.hasNextPage()) {

        break;

    }



    page = page.nextPage();

}

```



## Amazon Bedrock



This SDK also provides support for the

[Anthropic Bedrock API](https://aws.amazon.com/bedrock/claude/). This support

requires the `anthropic-java-bedrock` library dependency.



### Gradle



```kotlin

implementation("com.anthropic:anthropic-java-bedrock:2.1.0")

```



### Maven



```xml



    com.anthropic

    anthropic-java-bedrock

    2.1.0



```



### Usage



To use Anthropic on Bedrock, create the Anthropic client with the

[`BedrockBackend`](anthropic-java-bedrock/src/main/kotlin/com/anthropic/bedrock/backends/BedrockBackend.kt).

Usage of the API is otherwise the same.



```java

import com.anthropic.bedrock.backends.BedrockBackend;

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



AnthropicClient client = AnthropicOkHttpClient.builder()

        .backend(BedrockBackend.fromEnv())

        .build();

```



`BedrockBackend.fromEnv()` automatically resolves the AWS credentials using the

[AWS default credentials provider chain](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/credentials-chain.html)

and resolves the AWS region using the

[AWS default region provider chain](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/region-selection.html).

See those AWS documents for details on how to configure the AWS credentials and

AWS region for resolution by those provider chains.



Instead of resolving the AWS credentials and AWS region using the default AWS

provider chains, you can resolve them independently using any provider, or any

scheme of your choice, and pass them directly to the `BedrockBackend` during

building. For example, you can resolve the AWS credentials directly from

environment variables and hard-code the AWS region:



```java

import com.anthropic.bedrock.backends.BedrockBackend;

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;

import software.amazon.awssdk.auth.credentials.AwsCredentials;

import software.amazon.awssdk.regions.Region;



AwsCredentials awsCredentials = AwsBasicCredentials.create(

        System.getenv("AWS_ACCESS_KEY_ID"),

        System.getenv("AWS_SECRET_ACCESS_KEY"));



AnthropicClient client = AnthropicOkHttpClient.builder()

        .backend(BedrockBackend.builder()

                .awsCredentials(awsCredentials)

                .region(Region.US_EAST_1)

                .build())

        .build();

```



You can also create and configure your own AWS credentials provider and set it when building a

`BedrockBackend`. For example, you can use the AWS `DefaultCredentialsProvider`, but enable

automatic asynchronous refreshing of credentials:



```java

import com.anthropic.bedrock.backends.BedrockBackend;

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;

import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;



AwsCredentialsProvider awsCredentialsProvider =

        DefaultCredentialsProvider.builder()

                .asyncCredentialUpdateEnabled(true)

                .build();



AnthropicClient client = AnthropicOkHttpClient.builder()

        .backend(BedrockBackend.builder()

                .fromEnv(awsCredentialsProvider)

                .build())

        .build();

```



The AWS classes used above are included automatically as transitive dependencies

of the `anthropic-java-bedrock` library dependency. For other resolution

schemes, you may need additional AWS dependencies.



Currently, the Bedrock backend does _not_ support the following:



- Anthropic Batch API

- Anthropic Token Counting API



## Google Cloud Vertex AI



This SDK also provides support for Anthropic models on the

[Google Cloud Vertex AI](https://cloud.google.com/vertex-ai?hl=en) platform.

This support requires the `anthropic-java-vertex` library dependency.



### Gradle



```kotlin

implementation("com.anthropic:anthropic-java-vertex:2.1.0")

```



### Maven



```xml



    com.anthropic

    anthropic-java-vertex

    2.1.0



```



### Usage



To use Anthropic on Vertex AI, create the Anthropic client with the

`VertexBackend`. Usage of the API is otherwise the same.



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import com.anthropic.vertex.backends.VertexBackend;



AnthropicClient client = AnthropicOkHttpClient.builder()

        .backend(VertexBackend.fromEnv())

        .build();

```



`VertexBackend.fromEnv()` automatically resolves the Google OAuth2 credentials

from your configured Google Cloud

[Application Default Credentials](https://cloud.google.com/docs/authentication/provide-credentials-adc)

(ADC), the Google Cloud region from the `CLOUD_ML_REGION` environment variable,

and the Google Cloud project ID from `ANTHROPIC_VERTEX_PROJECT_ID` environment

variable. See the Google documentation for details on how to configure your ADC.



Instead of resolving the Google ADC, region and project ID automatically using

`fromEnv()`, you can resolve them independently using an alternative Google

Cloud facility, or any scheme of your choice, and pass them directly to the

`VertexBackend` during building. For example, you could resolve the Google

credentials and project ID directly from environment variables and hard-code the

Google Cloud region:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import com.anthropic.vertex.backends.VertexBackend;

import com.google.auth.oauth2.AccessToken;

import com.google.auth.oauth2.GoogleCredentials;



String accessToken = System.getenv("GOOGLE_APPLICATION_CREDENTIALS");

String project = System.getenv("ANTHROPIC_VERTEX_PROJECT_ID");



GoogleCredentials googleCredentials = GoogleCredentials.create(

        AccessToken.newBuilder().setTokenValue(accessToken).build());



AnthropicClient client = AnthropicOkHttpClient.builder()

        .backend(VertexBackend.builder()

                .googleCredentials(googleCredentials)

                .region("us-central1")

                .project(project)

                .build())

        .build();

```



The Google Cloud classes used above are included automatically as transitive

dependencies of the `anthropic-java-vertex` library dependency. For other

resolution schemes, you may need additional Google Cloud dependencies.



Currently, the Vertex backend does _not_ support the following:



- Anthropic Batch API



## Logging



The SDK uses the standard [OkHttp logging interceptor](https://github.com/square/okhttp/tree/master/okhttp-logging-interceptor).



Enable logging by setting the `ANTHROPIC_LOG` environment variable to `info`:



```sh

$ export ANTHROPIC_LOG=info

```



Or to `debug` for more verbose logging:



```sh

$ export ANTHROPIC_LOG=debug

```



## Jackson



The SDK depends on [Jackson](https://github.com/FasterXML/jackson) for JSON serialization/deserialization. It is compatible with version 2.13.4 or higher, but depends on version 2.18.2 by default.



The SDK throws an exception if it detects an incompatible Jackson version at runtime (e.g. if the default version was overridden in your Maven or Gradle config).



If the SDK threw an exception, but you're _certain_ the version is compatible, then disable the version check using the `checkJacksonVersionCompatibility` on [`AnthropicOkHttpClient`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClient.kt) or [`AnthropicOkHttpClientAsync`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClientAsync.kt).



> [!CAUTION]

> We make no guarantee that the SDK works correctly when the Jackson version check is disabled.



## Network options



### Retries



The SDK automatically retries 2 times by default, with a short exponential backoff.



Only the following error types are retried:



- Connection errors (for example, due to a network connectivity problem)

- 408 Request Timeout

- 409 Conflict

- 429 Rate Limit

- 5xx Internal



The API may also explicitly instruct the SDK to retry or not retry a response.



To set a custom number of retries, configure the client using the `maxRetries` method:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .fromEnv()

    .maxRetries(4)

    .build();

```



### Timeouts



Requests time out after 10 minutes by default.



However, for methods that accept `maxTokens`, if you specify a large `maxTokens` value and are _not_ streaming, then the default timeout will be calculated dynamically using this formula:



```java

Duration.ofSeconds(

    Math.min(

        60 * 60, // 1 hour max

        Math.max(

            10 * 60, // 10 minute minimum

            60 * 60 * maxTokens / 128_000

        )

    )

)

```



Which results in a timeout of up to 60 minutes, scaled by the `maxTokens` parameter, unless overridden.



To set a custom timeout, configure the method call using the `timeout` method:



```java

import com.anthropic.models.messages.Message;



Message message = client.messages().create(

  params, RequestOptions.builder().timeout(Duration.ofSeconds(30)).build()

);

```



Or configure the default for all method calls at the client level:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import java.time.Duration;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .fromEnv()

    .timeout(Duration.ofSeconds(30))

    .build();

```



### Proxies



To route requests through a proxy, configure the client using the `proxy` method:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;

import java.net.InetSocketAddress;

import java.net.Proxy;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .fromEnv()

    .proxy(new Proxy(

      Proxy.Type.HTTP, new InetSocketAddress(

        "https://example.com", 8080

      )

    ))

    .build();

```



### Custom HTTP client



The SDK consists of three artifacts:



- `anthropic-java-core`

  - Contains core SDK logic

  - Does not depend on [OkHttp](https://square.github.io/okhttp)

  - Exposes [`AnthropicClient`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClient.kt), [`AnthropicClientAsync`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientAsync.kt), [`AnthropicClientImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientImpl.kt), and [`AnthropicClientAsyncImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientAsyncImpl.kt), all of which can work with any HTTP client

- `anthropic-java-client-okhttp`

  - Depends on [OkHttp](https://square.github.io/okhttp)

  - Exposes [`AnthropicOkHttpClient`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClient.kt) and [`AnthropicOkHttpClientAsync`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClientAsync.kt), which provide a way to construct [`AnthropicClientImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientImpl.kt) and [`AnthropicClientAsyncImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientAsyncImpl.kt), respectively, using OkHttp

- `anthropic-java`

  - Depends on and exposes the APIs of both `anthropic-java-core` and `anthropic-java-client-okhttp`

  - Does not have its own logic



This structure allows replacing the SDK's default HTTP client without pulling in unnecessary dependencies.



#### Customized [`OkHttpClient`](https://square.github.io/okhttp/3.x/okhttp/okhttp3/OkHttpClient.html)



> [!TIP]

> Try the available [network options](#network-options) before replacing the default client.



To use a customized `OkHttpClient`:



1. Replace your [`anthropic-java` dependency](#installation) with `anthropic-java-core`

2. Copy `anthropic-java-client-okhttp`'s [`OkHttpClient`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/OkHttpClient.kt) class into your code and customize it

3. Construct [`AnthropicClientImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientImpl.kt) or [`AnthropicClientAsyncImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientAsyncImpl.kt), similarly to [`AnthropicOkHttpClient`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClient.kt) or [`AnthropicOkHttpClientAsync`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClientAsync.kt), using your customized client



### Completely custom HTTP client



To use a completely custom HTTP client:



1. Replace your [`anthropic-java` dependency](#installation) with `anthropic-java-core`

2. Write a class that implements the [`HttpClient`](anthropic-java-core/src/main/kotlin/com/anthropic/core/http/HttpClient.kt) interface

3. Construct [`AnthropicClientImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientImpl.kt) or [`AnthropicClientAsyncImpl`](anthropic-java-core/src/main/kotlin/com/anthropic/client/AnthropicClientAsyncImpl.kt), similarly to [`AnthropicOkHttpClient`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClient.kt) or [`AnthropicOkHttpClientAsync`](anthropic-java-client-okhttp/src/main/kotlin/com/anthropic/client/okhttp/AnthropicOkHttpClientAsync.kt), using your new client class



## Undocumented API functionality



The SDK is typed for convenient usage of the documented API. However, it also supports working with undocumented or not yet supported parts of the API.



### Parameters



To set undocumented parameters, call the `putAdditionalHeader`, `putAdditionalQueryParam`, or `putAdditionalBodyProperty` methods on any `Params` class:



```java

import com.anthropic.core.JsonValue;

import com.anthropic.models.messages.MessageCreateParams;



MessageCreateParams params = MessageCreateParams.builder()

    .putAdditionalHeader("Secret-Header", "42")

    .putAdditionalQueryParam("secret_query_param", "42")

    .putAdditionalBodyProperty("secretProperty", JsonValue.from("42"))

    .build();

```



These can be accessed on the built object later using the `_additionalHeaders()`, `_additionalQueryParams()`, and `_additionalBodyProperties()` methods.



> [!WARNING]

> The values passed to these methods overwrite values passed to earlier methods.

>

> For security reasons, ensure these methods are only used with trusted input data.



To set undocumented parameters on _nested_ headers, query params, or body classes, call the `putAdditionalProperty` method on the nested class:



```java

import com.anthropic.core.JsonValue;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Metadata;



MessageCreateParams params = MessageCreateParams.builder()

    .metadata(Metadata.builder()

        .putAdditionalProperty("secretProperty", JsonValue.from("42"))

        .build())

    .build();

```



These properties can be accessed on the nested built object later using the `_additionalProperties()` method.



To set a documented parameter or property to an undocumented or not yet supported _value_, pass a [`JsonValue`](anthropic-java-core/src/main/kotlin/com/anthropic/core/Values.kt) object to its setter:



```java

import com.anthropic.core.JsonValue;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;



MessageCreateParams params = MessageCreateParams.builder()

    .maxTokens(JsonValue.from(3.14))

    .addUserMessage("Hello, Claude")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .build();

```



The most straightforward way to create a [`JsonValue`](anthropic-java-core/src/main/kotlin/com/anthropic/core/Values.kt) is using its `from(...)` method:



```java

import com.anthropic.core.JsonValue;

import java.util.List;

import java.util.Map;



// Create primitive JSON values

JsonValue nullValue = JsonValue.from(null);

JsonValue booleanValue = JsonValue.from(true);

JsonValue numberValue = JsonValue.from(42);

JsonValue stringValue = JsonValue.from("Hello World!");



// Create a JSON array value equivalent to `["Hello", "World"]`

JsonValue arrayValue = JsonValue.from(List.of(

  "Hello", "World"

));



// Create a JSON object value equivalent to `{ "a": 1, "b": 2 }`

JsonValue objectValue = JsonValue.from(Map.of(

  "a", 1,

  "b", 2

));



// Create an arbitrarily nested JSON equivalent to:

// {

//   "a": [1, 2],

//   "b": [3, 4]

// }

JsonValue complexValue = JsonValue.from(Map.of(

  "a", List.of(

    1, 2

  ),

  "b", List.of(

    3, 4

  )

));

```



Normally a `Builder` class's `build` method will throw [`IllegalStateException`](https://docs.oracle.com/javase/8/docs/api/java/lang/IllegalStateException.html) if any required parameter or property is unset.



To forcibly omit a required parameter or property, pass [`JsonMissing`](anthropic-java-core/src/main/kotlin/com/anthropic/core/Values.kt):



```java

import com.anthropic.core.JsonMissing;

import com.anthropic.models.messages.MessageCreateParams;

import com.anthropic.models.messages.Model;



MessageCreateParams params = MessageCreateParams.builder()

    .addUserMessage("Hello, world")

    .model(Model.CLAUDE_3_7_SONNET_LATEST)

    .maxTokens(JsonMissing.of())

    .build();

```



### Response properties



To access undocumented response properties, call the `_additionalProperties()` method:



```java

import com.anthropic.core.JsonValue;

import java.util.Map;



Map additionalProperties = client.messages().create(params)._additionalProperties();

JsonValue secretPropertyValue = additionalProperties.get("secretProperty");



String result = secretPropertyValue.accept(new JsonValue.Visitor<>() {

    @Override

    public String visitNull() {

        return "It's null!";

    }



    @Override

    public String visitBoolean(boolean value) {

        return "It's a boolean!";

    }



    @Override

    public String visitNumber(Number value) {

        return "It's a number!";

    }



    // Other methods include `visitMissing`, `visitString`, `visitArray`, and `visitObject`

    // The default implementation of each unimplemented method delegates to `visitDefault`, which throws by default, but can also be overridden

});

```



To access a property's raw JSON value, which may be undocumented, call its `_` prefixed method:



```java

import com.anthropic.core.JsonField;

import java.util.Optional;



JsonField maxTokens = client.messages().create(params)._maxTokens();



if (maxTokens.isMissing()) {

  // The property is absent from the JSON response

} else if (maxTokens.isNull()) {

  // The property was set to literal null

} else {

  // Check if value was provided as a string

  // Other methods include `asNumber()`, `asBoolean()`, etc.

  Optional jsonString = maxTokens.asString();



  // Try to deserialize into a custom type

  MyClass myObject = maxTokens.asUnknown().orElseThrow().convert(MyClass.class);

}

```



### Response validation



In rare cases, the API may return a response that doesn't match the expected type. For example, the SDK may expect a property to contain a `String`, but the API could return something else.



By default, the SDK will not throw an exception in this case. It will throw [`AnthropicInvalidDataException`](anthropic-java-core/src/main/kotlin/com/anthropic/errors/AnthropicInvalidDataException.kt) only if you directly access the property.



If you would prefer to check that the response is completely well-typed upfront, then either call `validate()`:



```java

import com.anthropic.models.messages.Message;



Message message = client.messages().create(params).validate();

```



Or configure the method call to validate the response using the `responseValidation` method:



```java

import com.anthropic.models.messages.Message;



Message message = client.messages().create(

  params, RequestOptions.builder().responseValidation(true).build()

);

```



Or configure the default for all method calls at the client level:



```java

import com.anthropic.client.AnthropicClient;

import com.anthropic.client.okhttp.AnthropicOkHttpClient;



AnthropicClient client = AnthropicOkHttpClient.builder()

    .fromEnv()

    .responseValidation(true)

    .build();

```



## FAQ



### Why don't you use plain `enum` classes?



Java `enum` classes are not trivially [forwards compatible](https://www.stainless.com/blog/making-java-enums-forwards-compatible). Using them in the SDK could cause runtime exceptions if the API is updated to respond with a new enum value.



### Why do you represent fields using `JsonField` instead of just plain `T`?



Using `JsonField` enables a few features:



- Allowing usage of [undocumented API functionality](#undocumented-api-functionality)

- Lazily [validating the API response against the expected shape](#response-validation)

- Representing absent vs explicitly null values



### Why don't you use [`data` classes](https://kotlinlang.org/docs/data-classes.html)?



It is not [backwards compatible to add new fields to a data class](https://kotlinlang.org/docs/api-guidelines-backward-compatibility.html#avoid-using-data-classes-in-your-api) and we don't want to introduce a breaking change every time we add a field to a class.



### Why don't you use checked exceptions?



Checked exceptions are widely considered a mistake in the Java programming language. In fact, they were omitted from Kotlin for this reason.



Checked exceptions:



- Are verbose to handle

- Encourage error handling at the wrong level of abstraction, where nothing can be done about the error

- Are tedious to propagate due to the [function coloring problem](https://journal.stuffwithstuff.com/2015/02/01/what-color-is-your-function)

- Don't play well with lambdas (also due to the function coloring problem)



## Semantic versioning



This package generally follows [SemVer](https://semver.org/spec/v2.0.0.html) conventions, though certain backwards-incompatible changes may be released as minor versions:



1. Changes to library internals which are technically public but not intended or documented for external use. _(Please open a GitHub issue to let us know if you are relying on such internals.)_

2. Changes that we do not expect to impact the vast majority of users in practice.



We take backwards-compatibility seriously and work hard to ensure you can rely on a smooth upgrade experience.



We are keen for your feedback; please open an [issue](https://www.github.com/anthropics/anthropic-sdk-java/issues) with questions, bugs, or suggestions.