Anthropic API Free API Guide

Provider fit matrix

Production readiness checklist

Python setup snapshot

Start with the smallest possible chat completion, then move the key to your server-side secret manager before production.

from anthropic import Anthropic

client = Anthropic(api_key="your-key")

message = client.messages.create(
    model="claude-sonnet-4-20250514",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}]
)
print(message.content[0].text)

cURL smoke test

Use this to verify endpoint, auth header, model name, response shape, and quota before adding SDK abstractions.

curl https://api.provider.example/v1/chat/completions \
  -H "Authorization: Bearer $CLAUDE_API_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "Claude Opus 4",
    "messages": [{"role": "user", "content": "Hello from yangmao.ai"}]
  }'

Decision checklist

Related internal links

FAQ