Careeroza

Setup and API Key

Install the SDK

Example

Inside your virtual environment:

pip install anthropic python-dotenv

Example output

Successfully installed anthropic-1.x ...
# .env
ANTHROPIC_API_KEY=sk-ant-api03-xxxxxxxxxxxxxxxx
from dotenv import load_dotenv
import anthropic

load_dotenv()                    # loads ANTHROPIC_API_KEY from .env
client = anthropic.Anthropic()   # picks up ANTHROPIC_API_KEY automatically

What the SDK Sends

Example

The SDK is a convenient wrapper around one HTTPS request: POST https://api.anthropic.com/v1/messages with a JSON body. Building that request yourself shows there is no magic (this does not send anything):

import json

api_key = "sk-ant-api03-demo-key-1234"
headers = {
    "x-api-key": api_key[:10] + "...",          # masked for printing
    "anthropic-version": "2023-06-01",
    "content-type": "application/json",
}
body = {
    "model": "claude-opus-5-5",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello, Claude"}],
}
print("POST https://api.anthropic.com/v1/messages")
for k, v in headers.items():
    print(f"{k}: {v}")
print()
print(json.dumps(body, indent=2))

Output

POST https://api.anthropic.com/v1/messages
x-api-key: sk-ant-api...
anthropic-version: 2023-06-01
content-type: application/json

{
  "model": "claude-opus-5-5",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": "Hello, Claude"
    }
  ]
}

Example

The same call with curl:

curl https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{"model": "claude-opus-5-5", "max_tokens": 1024,
       "messages": [{"role": "user", "content": "Hello, Claude"}]}'