​
Prerequisites

​
Call the API

1

Set your API key

Get your API key from the Claude Console and set it as an environment variable:
export ANTHROPIC_API_KEY='your-api-key-here'
2

Make your first API call

Run this command to create a simple web search assistant:
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-sonnet-4-5",  "max_tokens": 1000,  "messages": [  {  "role": "user",   "content": "What should I search for to find the latest developments in renewable energy?"  }  ]  }'
Example output:
{  "id": "msg_01HCDu5LRGeP2o7s2xGmxyx8",  "type": "message",   "role": "assistant",  "content": [  {  "type": "text",  "text": "Here are some effective search strategies to find the latest renewable energy developments:\n\n## Search Terms to Use:\n- \"renewable energy news 2024\"\n- \"clean energy breakthrough\"\n- \"solar/wind/battery technology advances\"\n- \"green energy innovations\"\n- \"climate tech developments\"\n- \"energy storage solutions\"\n\n## Best Sources to Check:\n\n**News & Industry Sites:**\n- Renewable Energy World\n- GreenTech Media (now Wood Mackenzie)\n- Energy Storage News\n- CleanTechnica\n- PV Magazine (for solar)\n- WindPower Engineering & Development..."  }  ],  "model": "claude-sonnet-4-5",  "stop_reason": "end_turn",  "usage": {  "input_tokens": 21,  "output_tokens": 305  } }

​
Next steps

Now that you have made your first Claude API request, it’s time to explore what else is possible:

Features Overview

Explore Claude’s advanced features and capabilities.

Client SDKs

Discover Anthropic client libraries.

Claude Cookbook

Learn with interactive Jupyter notebooks.