Vertex AI API

The Vertex API for accessing Claude is nearly-identical to the Messages API and supports all of the same options, with two key differences:

• In Vertex, model is not passed in the request body. Instead, it is specified in the Google Cloud endpoint URL.
• In Vertex, anthropic_version is passed in the request body (rather than as a header), and must be set to the value vertex-2023-10-16.

Vertex is also supported by Anthropic’s official client SDKs. This guide will walk you through the process of making a request to Claude on Vertex AI in either Python or TypeScript.

Note that this guide assumes you have already have a GCP project that is able to use Vertex AI. See using the Claude 3 models from Anthropic for more information on the setup required, as well as a full walkthrough.

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Install an SDK for accessing Vertex AI

First, install Anthropic’s client SDK for your language of choice.

pip install -U google-cloud-aiplatform "anthropic[vertex]"

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Accessing Vertex AI

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Model Availability

Note that Anthropic model availability varies by region. Search for “Claude” in the Vertex AI Model Garden or go to Use Claude 3 for the latest information.

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API model names

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Making requests

Before running requests you may need to run gcloud auth application-default login to authenticate with GCP.

The following examples shows how to generate text from Claude on Vertex AI:

from anthropic import AnthropicVertex

project_id = "MY_PROJECT_ID"
# Where the model is running
region = "us-east5"

client = AnthropicVertex(project_id=project_id, region=region)

message = client.messages.create(
    model="claude-opus-4@20250514",
    max_tokens=100,
    messages=[
        {
            "role": "user",
            "content": "Hey Claude!",
        }
    ],
)
print(message)

See our client SDKs and the official Vertex AI docs for more details.

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Activity logging

Vertex provides a request-response logging service that allows customers to log the prompts and completions associated with your usage.

Anthropic recommends that you log your activity on at least a 30-day rolling basis in order to understand your activity and investigate any potential misuse.

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Feature support

You can find all the features currently supported on Vertex here.