MessagesFirst steps

Get started with Claude

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

Prerequisites

An Anthropic Console account
An API key

Call the API

Set your API key
Export your API key as an environment variable. The cURL command below reads it from $ANTHROPIC_API_KEY.
export ANTHROPIC_API_KEY="your-api-key-here"

Make your first API call

Send a POST request to the Messages API:

cURL

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-4-8",
    "max_tokens": 1000,
    "messages": [
      {
        "role": "user",
        "content": "What should I search for to find the latest developments in renewable energy?"
      }
    ]
  }'

Claude returns a JSON response containing the assistant's message:

Output

{
  "id": "msg_013mHbppMPd2PrVJzGMZPt2D",
  "type": "message",
  "role": "assistant",
  "model": "claude-opus-4-8",
  "content": [
    {
      "type": "text",
      "text": "Here are some effective search strategies to find the latest developments in renewable energy:\n\n## General Search Terms\n- \"Renewable energy news 2025\"\n- ..."
    }
  ],
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 21,
    "output_tokens": 305
  }
}

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.

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Call the API

Set your API key
Export your API key as an environment variable. The cURL command below reads it from $ANTHROPIC_API_KEY.
export ANTHROPIC_API_KEY="your-api-key-here"

Make your first API call

Send a POST request to the Messages API:

cURL

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-4-8",
    "max_tokens": 1000,
    "messages": [
      {
        "role": "user",
        "content": "What should I search for to find the latest developments in renewable energy?"
      }
    ]
  }'

Claude returns a JSON response containing the assistant's message:

Output

{
  "id": "msg_013mHbppMPd2PrVJzGMZPt2D",
  "type": "message",
  "role": "assistant",
  "model": "claude-opus-4-8",
  "content": [
    {
      "type": "text",
      "text": "Here are some effective search strategies to find the latest developments in renewable energy:\n\n## General Search Terms\n- \"Renewable energy news 2025\"\n- ..."
    }
  ],
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 21,
    "output_tokens": 305
  }
}

Prerequisites

Call the API

Next steps

Prerequisites

Call the API

Next steps

Prerequisites

Call the API

Next steps

Prerequisites

Call the API

Next steps