Claude Python SDK Installation Guide

Written by Michael Lip · Solo founder of Zovo · $400K+ on Upwork · 100% JSS Join 50+ builders · More at zovo.one

The Anthropic Python SDK is the fastest way to start building with Claude. This guide covers installation, platform-specific extras, and your first API call.

Quick Fix

Install the SDK and make your first call in under 2 minutes:

pip install anthropic
export ANTHROPIC_API_KEY="sk-ant-your-key-here"

import anthropic
client = anthropic.Anthropic()
message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello, Claude"}]
)
print(message.content[0].text)

What You Need

Full Solution

Install the Base SDK

pip install anthropic

Install Platform-Specific Extras

If you are using Claude through AWS Bedrock, Google Vertex AI, or need better async performance:

# Amazon Bedrock support
pip install anthropic[bedrock]

# Google Vertex AI support
pip install anthropic[vertex]

# Improved async performance with aiohttp
pip install anthropic[aiohttp]

# Multiple extras at once
pip install anthropic[bedrock,vertex,aiohttp]

Set Your API Key

The SDK reads the ANTHROPIC_API_KEY environment variable automatically:

# Linux / macOS (add to ~/.bashrc or ~/.zshrc for persistence)
export ANTHROPIC_API_KEY="sk-ant-your-key-here"

# Windows PowerShell
$env:ANTHROPIC_API_KEY = "sk-ant-your-key-here"

Or pass it explicitly (not recommended for production):

import anthropic
client = anthropic.Anthropic(api_key="sk-ant-your-key-here")

Synchronous Usage

import anthropic

client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Explain quantum computing in 3 sentences."}]
)

print(message.content[0].text)
print(f"Tokens: {message.usage.input_tokens} in, {message.usage.output_tokens} out")

Async Usage

from anthropic import AsyncAnthropic

client = AsyncAnthropic()

async def main():
    message = await client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
        messages=[{"role": "user", "content": "Hello"}]
    )
    print(message.content[0].text)

import asyncio
asyncio.run(main())

Async with aiohttp (Better Performance)

from anthropic import AsyncAnthropic, DefaultAioHttpClient

async def main():
    async with AsyncAnthropic(http_client=DefaultAioHttpClient()) as client:
        message = await client.messages.create(
            model="claude-sonnet-4-6",
            max_tokens=1024,
            messages=[{"role": "user", "content": "Hello"}]
        )
        print(message.content[0].text)

import asyncio
asyncio.run(main())

Platform Integrations

Use Claude through cloud providers with their respective clients:

import anthropic

# Amazon Bedrock
bedrock_client = anthropic.AnthropicBedrock()

# Google Vertex AI
vertex_client = anthropic.AnthropicVertex(
    project_id="your-gcp-project",
    region="us-east5"
)

# Microsoft Foundry
foundry_client = anthropic.AnthropicFoundry()

Enable Debug Logging

ANTHROPIC_LOG=debug python your_script.py

Configure Retries and Timeouts

import anthropic
import httpx

# Custom retries (default: 2)
client = anthropic.Anthropic(max_retries=5)

# Custom timeout (default: 10 minutes)
client = anthropic.Anthropic(timeout=20.0)

# Fine-grained timeout control
client = anthropic.Anthropic(
    timeout=httpx.Timeout(60.0, read=5.0, write=10.0, connect=2.0)
)

Prevention

  1. Pin your SDK version: Use pip install anthropic==X.Y.Z in production to avoid breaking changes.
  2. Use environment variables: Never hardcode API keys in source code.
  3. Use a virtual environment: python -m venv .venv && source .venv/bin/activate before installing.
  4. Check Python version: The SDK requires Python 3.9+. Run python --version to verify.