# Check Username Availability

Check if a username is available for registration. No authentication required.

## Request Body

**`username`** string required

Username to check (3-100 characters).

## Returns

Availability status and message.

Request

```bash
curl -X POST \
  "https://api.aitronos.com/v1/user/username/check-availability" \
  -H "Content-Type: application/json" \
  -d '{
    "username": "johndoe"
  }'
```


```python
import requests

response = requests.post(
    "https://api.aitronos.com/v1/user/username/check-availability",
    json={"username": "johndoe"}
)
```


```javascript
const response = await fetch('https://api.aitronos.com/v1/user/username/check-availability', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ username: 'johndoe' })
});
```

**Response:**

200 OK - Available

```json
{
  "available": true,
  "username": "johndoe",
  "message": "Username is available"
}
```

200 OK - Taken

```json
{
  "available": false,
  "username": "johndoe",
  "message": "Username is already taken"
}
```