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

# Inference API

> The data plane — send LLM requests through Relay

The inference plane is the customer-facing data plane. It listens on
`RELAY_PORT` (default `8080`) and speaks OpenAI- and Anthropic-shape wire
protocols, plus Relay's own provider-neutral canonical shape.

## Authentication

Every inference request authenticates with a **relay key** as a bearer token:

```
Authorization: Bearer <relay-key>
```

Relay keys are minted in the admin UI or via the control plane
(`POST /api/relay-keys`). The plaintext is shown exactly once on creation —
Relay stores only `sha256(plaintext)`.

## Namespacing

Each vendor wire shape is served under its own path prefix. The bare `/v1`
namespace belongs to Relay's canonical shape.

| Prefix           | Wire shape                                     |
| ---------------- | ---------------------------------------------- |
| `/openai/...`    | OpenAI Chat Completions, Responses, Embeddings |
| `/anthropic/...` | Anthropic Messages                             |
| `/v1/...`        | Relay canonical (provider-neutral)             |

## Endpoints

| Method | Path                          | Shape                              |
| ------ | ----------------------------- | ---------------------------------- |
| `POST` | `/openai/v1/chat/completions` | OpenAI Chat Completions            |
| `POST` | `/openai/v1/responses`        | OpenAI Responses API               |
| `POST` | `/openai/v1/embeddings`       | OpenAI Embeddings (byte-pass)      |
| `POST` | `/anthropic/v1/messages`      | Anthropic Messages                 |
| `POST` | `/v1/generate`                | Relay canonical request/response   |
| `GET`  | `/v1/models`                  | Models accessible to the relay key |
| `GET`  | `/healthz`                    | Liveness + Postgres ping (public)  |
| `GET`  | `/openapi.json`               | Generated typed OpenAPI spec       |

## Examples

<CodeGroup>
  ```bash OpenAI Chat Completions theme={null}
  curl http://localhost:8080/openai/v1/chat/completions \
    -H "Authorization: Bearer <relay-key>" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "gpt-4o",
      "messages": [{"role": "user", "content": "hello"}]
    }'
  ```

  ```bash Anthropic Messages theme={null}
  curl http://localhost:8080/anthropic/v1/messages \
    -H "Authorization: Bearer <relay-key>" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "claude-sonnet-4-6",
      "max_tokens": 256,
      "messages": [{"role": "user", "content": "hello"}]
    }'
  ```

  ```bash Streaming (SSE) theme={null}
  curl http://localhost:8080/openai/v1/chat/completions \
    -H "Authorization: Bearer <relay-key>" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "gpt-4o",
      "stream": true,
      "messages": [{"role": "user", "content": "hello"}]
    }'
  ```
</CodeGroup>

<Info>
  Responses stream byte-for-byte from the upstream when the inbound shape
  matches the upstream shape. Cross-shape requests (e.g. OpenAI in,
  Anthropic upstream) are translated per chunk through Relay's canonical
  protocol.
</Info>

## Models

The `model` field is resolved against your catalog. A model is reachable
only if a policy grants it to your relay key **and** the model has an
enabled host binding with a healthy host key. List what your key can reach:

```bash theme={null}
curl http://localhost:8080/v1/models \
  -H "Authorization: Bearer <relay-key>"
```

## Errors

| Status        | Meaning                                                                                       |
| ------------- | --------------------------------------------------------------------------------------------- |
| `401`         | Missing or invalid relay key.                                                                 |
| `403`         | Relay key's policy does not grant the requested model.                                        |
| `404`         | Unknown model, or no enabled binding for it.                                                  |
| `429`         | Rate limit reached (relay-side or upstream).                                                  |
| `502` / `503` | No healthy key in the pool, or upstream unreachable. See [Troubleshooting](/troubleshooting). |

<Warning>
  Relay does not fail over mid-stream. Failover across keys and hosts
  happens **before the first byte** reaches you. Once bytes flow, an
  upstream error is returned as-is.
</Warning>