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How to get Anthropic API key

Q: How to get Anthropic API key

To get an Anthropic API key, sign up or log in at the Anthropic developer portal and generate a new API key from your account dashboard. Use this key securely in your code by setting it as an environment variable like ANTHROPIC_API_KEY.

Quick answer

To get an Anthropic API key, sign up or log in at the Anthropic developer portal and generate a new API key from your account dashboard. Use this key securely in your code by setting it as an environment variable like ANTHROPIC_API_KEY.

PREREQUISITES

Python 3.8+
pip install anthropic>=0.20
Anthropic account registration

Setup

First, create an account at the Anthropic developer portal. After verifying your email, log in to access your dashboard. Navigate to the API keys section to generate a new API key. Store this key securely and set it as an environment variable ANTHROPIC_API_KEY on your local machine or server.

Install the official Anthropic Python SDK with:

bash

pip install anthropic>=0.20

Step by step

Use the following Python code to verify your API key and make a simple request to Anthropic's claude-3-5-sonnet-20241022 model. This example demonstrates the correct SDK usage pattern with environment variable authentication.

python

import os
import anthropic

client = anthropic.Anthropic(api_key=os.environ["ANTHROPIC_API_KEY"])

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=100,
    system="You are a helpful assistant.",
    messages=[{"role": "user", "content": "Hello, how do I get an Anthropic API key?"}]
)

print(response.content[0].text)

output

Hello! To get an Anthropic API key, sign up at the Anthropic developer portal and generate your key in the dashboard.

Common variations

You can use different Anthropic models by changing the model parameter, for example to claude-3-opus-20240229. The SDK also supports asynchronous calls using asyncio. For streaming responses, use the stream=True parameter in client.messages.create. Always keep your API key secure and never hardcode it in source code.

python

import asyncio
import os
import anthropic

async def main():
    client = anthropic.Anthropic(api_key=os.environ["ANTHROPIC_API_KEY"])
    response = await client.messages.acreate(
        model="claude-3-opus-20240229",
        max_tokens=100,
        system="You are a helpful assistant.",
        messages=[{"role": "user", "content": "Async example with Anthropic."}]
    )
    print(response.content[0].text)

asyncio.run(main())

output

Hello! This is an async example showing how to call Anthropic's API.

Troubleshooting

If you receive an authentication error, verify that your ANTHROPIC_API_KEY environment variable is set correctly and has no extra spaces. Check your account dashboard to ensure your key is active. For network errors, confirm your internet connection and firewall settings. If you hit rate limits, review your usage and consider contacting Anthropic support.

✅

Key Takeaways

Register at Anthropic's developer portal to generate your API key securely.
Always set your API key as an environment variable named ANTHROPIC_API_KEY.
Use the official Anthropic Python SDK with the latest model names for best results.

Verified 2026-04 · claude-3-5-sonnet-20241022, claude-3-opus-20240229

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