Claude API · Setup and first request

Send your first message (curl)

The raw HTTP request behind the SDKs. Parse responses with jq rather than grep.

curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2026-10-21" \
  -d '{
    "model": "claude-opus-5-5",
    "max_tokens": 16000,
    "messages": [{"role": "user", "content": "What is the capital of France?"}]
  }'

Official Claude API documentation

More setup and first request commands

Install the Python SDK
Install the TypeScript SDK
Set your API key
Send your first message (Python)
Send your first message (TypeScript)
Pick a model

All setup and first request commands · Claude API cheatsheet