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Overview

The passthrough API is in beta. Use it when you need a provider-native API shape, and prefer the OpenAI-compatible /v1 routes when you need the most stable GoModel interface.
The passthrough API proxies provider-native requests through GoModel without translating the request or response body. Use it when a client library expects a provider’s native API instead of the OpenAI-compatible API. For example, the Anthropic SDK sends requests to /v1/messages, so you can point it at GoModel’s Anthropic passthrough base URL: 
http://localhost:8080/p/anthropic
The SDK sends: 
POST /p/anthropic/v1/messages
GoModel normalizes the optional v1 segment and forwards the request upstream as Anthropic’s native: 
POST /messages

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How it works

Passthrough routes use this shape: 
/p/{provider}/{endpoint}
For Anthropic, these two paths map to the same upstream endpoint when ALLOW_PASSTHROUGH_V1_ALIAS=true, which is the default: 
/p/anthropic/messages
/p/anthropic/v1/messages
GoModel handles gateway authentication first. If GOMODEL_MASTER_KEY or managed auth keys are enabled, the client must send a GoModel bearer token: 
Authorization: Bearer change-me
GoModel strips client Authorization and X-Api-Key headers before forwarding the request, then applies the upstream provider credential configured on the server. For Anthropic, GoModel uses its configured ANTHROPIC_API_KEY. Because passthrough is provider-native, the response is also provider-native. For Anthropic messages, the response uses Anthropic’s message schema, not an OpenAI chat completion schema.

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Anthropic SDK example

Set the Anthropic SDK base URL to GoModel’s Anthropic passthrough route. Use the GoModel token as Anthropic SDK bearer auth. 
import os
from anthropic import Anthropic

client = Anthropic(
    base_url="http://localhost:8080/p/anthropic",
    auth_token=os.environ["GOMODEL_MASTER_KEY"],
)

message = client.messages.create(
    model="claude-3-haiku-20240307",
    max_tokens=16,
    messages=[
        {
            "role": "user",
            "content": "Reply with exactly ok",
        }
    ],
)

print(message.content[0].text)
If your gateway does not require authentication, use a dummy SDK API key such as not-needed instead of auth_token or authToken. GoModel strips X-Api-Key from passthrough requests before forwarding them upstream.

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Current limitations

Passthrough is intentionally narrow while the API is in beta.
  • openai, anthropic, openrouter, and zai are enabled by default.
  • GoModel does not translate passthrough request bodies or response bodies.
  • Provider-native error bodies and status codes are proxied instead of converted into OpenAI-compatible responses.
  • Features that depend on OpenAI-compatible request or response shapes may not apply to passthrough traffic in the same way as /v1 traffic.
Passthrough routes are enabled by default: 
ENABLE_PASSTHROUGH_ROUTES=true
ALLOW_PASSTHROUGH_V1_ALIAS=true
ENABLED_PASSTHROUGH_PROVIDERS=openai,anthropic,openrouter,zai
Set ENABLED_PASSTHROUGH_PROVIDERS to the provider types you want to expose.