Get started with Claude - Claude Platform Docs
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MessagesFirst steps

Get started with Claude

Make your first API call to Claude and build a simple web search assistant.

Prerequisites

Call the API

  1. Set your API key

    Export your API key as an environment variable. The SDK reads ANTHROPIC_API_KEY automatically.

    export ANTHROPIC_API_KEY="your-api-key-here"

  2. Create a project and install the SDK

    mkdir claude-quickstart && cd claude-quickstart
python3 -m venv .venv && source .venv/bin/activate
pip install anthropic

  3. Create your code

    Create a file called quickstart.py:

    Python
    import anthropic

client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-opus-5",
    max_tokens=1000,
    messages=[
        {
            "role": "user",
            "content": "What should I search for to find the latest developments in renewable energy?",
        }
    ],
)

for block in message.content:
    if block.type == "text":
        print(block.text)

  4. Run your code

    python quickstart.py
    Output
    Here are some effective search strategies to find the latest developments in renewable energy:

## General Search Terms
- "Renewable energy news 2025"
- ...

Next steps

You made your first API call. Next, learn the Messages API patterns you'll use in every Claude integration.

Working with the Messages API

Learn multi-turn conversations, system prompts, stop reasons, and other core patterns.

Once you're comfortable with the basics, explore further:

Models overview

Compare Claude models by capability and cost.

Features overview

Browse all Claude capabilities: tools, context management, structured outputs, and more.

Client SDKs

Reference documentation for Python, TypeScript, C#, and other client libraries.

Authentication

Compare API keys and Workload Identity Federation, and set key expiration.

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