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

# Chat Completions

> Chat with your deployed playbook over an OpenAI-compatible endpoint.

Send messages to your deployed playbook. Any OpenAI-compatible SDK works — just
swap the base URL, API key, and `model`.

<Note>
  **Prerequisites:** A deployed playbook + API key. See [Authentication](/api/get-started/authentication).
</Note>

### Headers

| Name          | Type   | Required | Description             |
| ------------- | ------ | -------- | ----------------------- |
| Authorization | string | Yes      | `Bearer <your-api-key>` |
| Content-Type  | string | Yes      | `application/json`      |

### Request body

| Field    | Type   | Required | Description                               |
| -------- | ------ | -------- | ----------------------------------------- |
| model    | string | Yes      | Playbook id with `public:` prefix         |
| messages | array  | Yes      | Array of `{role, content}` objects        |
| user     | string | No       | Stable session id → stateful conversation |

<ResponseExample>
  ```json 200 theme={null}
  {
    "id": "chatcmpl-abc123",
    "object": "chat.completion",
    "created": 1677858242,
    "model": "public:PB_7ZRMzCA1ojQ9LlcK",
    "choices": [
      {
        "index": 0,
        "message": {
          "role": "assistant",
          "content": "Hi! Welcome to Lumina Spa - I'm Mira, your booking assistant. How can I help you today?"
        },
        "finish_reason": "stop"
      }
    ],
    "usage": {
      "prompt_tokens": 10,
      "completion_tokens": 20,
      "total_tokens": 30
    }
  }
  ```

  ```json 401 theme={null}
  {
    "error": {
      "message": "Invalid API key",
      "type": "authentication_error",
      "code": "invalid_api_key"
    }
  }
  ```
</ResponseExample>

```bash cURL theme={null}
# Basic chat completion
curl -X POST "https://inference.unpod.ai/v1/chat/completions" \
  -H "Authorization: Bearer your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"public:PB_7ZRMzCA1ojQ9LlcK","messages":[{"role":"user","content":"hi"}]}'

# With session id — stateful conversation
curl -X POST "https://inference.unpod.ai/v1/chat/completions" \
  -H "Authorization: Bearer your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"public:PB_7ZRMzCA1ojQ9LlcK","messages":[{"role":"user","content":"hi"}],"user":"sess_abc"}'
```