# GET /api/v1/businesses/mailbox

> Check mailbox uniqueness

- **Tag:** businesses
- **Operation ID:** `check_mailbox_uniqueness_api_v1_businesses_mailbox_get`

## Description

Check if a mailbox is unique; validation and conflicts are handled by the service.

Rate-limited per user and per IP — the endpoint is otherwise an
enumeration oracle for the mailbox namespace.

## Authentication

Bearer token in `Authorization` header.
Required header: `x-business-id: <business uuid>`.

## Parameters

- `mailbox` (query, string, required) — Mailbox to check for uniqueness

## Responses

### 200 — Successful Response

Schema: `MailboxUniquenessResponse`

- `unique` (boolean · required) — Whether the mailbox is unique

### 400 — Bad Request - Invalid input

### 409 — Conflict - Resource already exists

### 422 — Validation Error

Schema: `HTTPValidationError`

- `detail` (array · ValidationError) → `ValidationError`
  - `loc` (array · string | integer · required)
  - `msg` (string · required)
  - `type` (string · required)
  - `input` (object)
  - `ctx` (object)

### 429 — Too Many Requests - Rate limit exceeded

## Code samples

### cURL

```bash
curl -X GET 'https://api.ondayzero.com/api/v1/businesses/mailbox' \
  -H 'Authorization: Bearer dz_your_token' \
  -H 'x-business-id: YOUR_BUSINESS_ID'
```

### JavaScript

```javascript
const response = await fetch('https://api.ondayzero.com/api/v1/businesses/mailbox', {
  method: 'GET',
  headers: {
    Authorization: 'Bearer dz_your_token',
    'x-business-id': 'YOUR_BUSINESS_ID',
  },
});
const data = await response.json();
```

### Python

```python
import httpx

headers = {
    "Authorization": "Bearer dz_your_token",
    "x-business-id": "YOUR_BUSINESS_ID",
}

response = httpx.get("https://api.ondayzero.com/api/v1/businesses/mailbox", headers=headers)
data = response.json()
```

## See also

- HTML version: https://www.ondayzero.com/docs/reference/businesses/check-mailbox-uniqueness
- OpenAPI slice: https://www.ondayzero.com/docs/reference/businesses/check-mailbox-uniqueness/openapi.json
- Other endpoints in **businesses**: https://www.ondayzero.com/docs/reference/businesses