> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tulipai.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Gateway overview

> The Tulip Gateway API for model discovery, quotes, inference, provider onboarding, and settlement.

The Tulip v1 Gateway is an offer-aware proxy for verified Hugging Face Inference Endpoints. It exposes an OpenAI-compatible chat route while adding model-credit quotes, permit validation, provider routing, metering, and signed receipts.

<Info>
  Hugging Face is the first Gateway adapter, not Tulip's permanent vendor boundary. Later versions may add other model registries, endpoint vendors, GPU networks, and execution environments.
</Info>

## Base URL

Use the production base URL issued with your Tulip API credentials. The examples refer to it as `TULIP_GATEWAY_URL`. Send credentials only to that origin.

## Capabilities

* Lists canonical models and public provider offer metadata.
* Selects the cheapest eligible offer for a request.
* Reserves a maximum credit charge against an inference permit.
* Wakes sleeping Hugging Face endpoints when required.
* Proxies non-streaming and streaming chat completions.
* Requires exact upstream token usage.
* Signs offer-bound EIP-712 usage receipts.
* Onboards provider endpoints without exposing their credentials publicly.
* Submits completed receipts to the inference escrow in batches.

## Compatibility

`POST /v1/chat/completions` accepts the common OpenAI chat completion fields used by the selected endpoint, including messages, generation limits, tools, response format, and streaming options.

Tulip adds:

* Optional `offer` in the request body for explicit provider selection.
* `X-Tulip-Permit` for credit authorization.
* Optional `X-Tulip-Quote` for an existing request-bound quote.
* Tulip response headers identifying routing and charges.

## Public and private data

Public model and offer responses include repository identity, on-chain addresses, operator, payout, status, capabilities, hardware metadata, and verification times.

They never include the provider's endpoint URL or Hugging Face access token.

## Error format

Gateway errors use a consistent object:

```json theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
{
  "error": {
    "code": "no_eligible_offer",
    "type": "no_eligible_offer",
    "message": "No verified active provider offer is available"
  }
}
```

<Card title="Authentication and headers" icon="key-round" href="/gateway-reference/authentication">
  Configure API keys, inference permits, quotes, and provider signatures.
</Card>