Anthropic SDK (gateway)

Route Anthropic SDK calls through the Respan gateway. Only your RESPAN_API_KEY is needed — no separate ANTHROPIC_API_KEY required.

Setup

Install packages

$ pip install anthropic

Set environment variables

$ export RESPAN_API_KEY="YOUR_RESPAN_API_KEY"

No ANTHROPIC_API_KEY needed — the Respan gateway handles provider authentication.

Point the Anthropic client to the Respan gateway

1 import os
2 from anthropic import Anthropic
3 
4 client = Anthropic(
5     api_key=os.environ["RESPAN_API_KEY"],
6     base_url="https://api.respan.ai/api/anthropic/",
7 )
8 
9 message = client.messages.create(
10     model="claude-sonnet-4-5-20250929",
11     max_tokens=1024,
12     messages=[{"role": "user", "content": "Say hello in three languages."}],
13 )
14 print(message.content[0].text)

Switch models

Change the model parameter to use different Claude models through the same gateway.

1 message = client.messages.create(model="claude-sonnet-4-5-20250929", max_tokens=1024, messages=messages)
2 message = client.messages.create(model="claude-haiku-4-5-20251001", max_tokens=1024, messages=messages)
3 message = client.messages.create(model="claude-opus-4-5-20251101", max_tokens=1024, messages=messages)

See the full model list.

Respan parameters

Pass additional Respan parameters via metadata under the respan_params key for gateway features.

1 message = client.messages.create(
2     model="claude-sonnet-4-5-20250929",
3     max_tokens=1024,
4     messages=[{"role": "user", "content": "Hello"}],
5     metadata={
6         "respan_params": {
7             "customer_identifier": "user_123",
8             "metadata": {"session_id": "abc123"},
9             "thread_identifier": "conversation_456",
10         }
11     },
12 )

See Respan params & metadata for the full list.