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

# POST /api/auth/phone/send-otp — send SMS verification code

> Send a one-time SMS verification code to a phone number to use with phone registration or sign-in. Rate limited to prevent abuse.

Send a one-time SMS verification code to a phone number. Use the returned code with `POST /api/auth/register/phone` to create an account, or with a phone-based login flow.

**Method:** `POST` **Path:** `/api/auth/phone/send-otp` **Auth:** None

## Request

<ParamField body="phone" type="string" required>
  E.164-formatted phone number.
</ParamField>

## Response

Returns `202 Accepted` with an empty body on success. The SMS is delivered asynchronously.

## Example

```bash theme={null}
curl -X POST https://ariacompute.com/api/auth/phone/send-otp \
  -H "Content-Type: application/json" \
  -d '{"phone": "+8613800138000"}'
```

## Errors

| Status | Meaning                                |
| ------ | -------------------------------------- |
| `400`  | Missing or malformed `phone`.          |
| `429`  | Too many requests for the same number. |


## Related topics

- [POST /api/auth/register/phone — create account with phone](/api-reference/auth/register-phone.md)
- [Authenticate requests to the Aria Compute API](/authentication.md)
- [POST /api/auth/register/email — create account with email](/api-reference/auth/register-email.md)
- [Prepaid wallet, top-ups, and usage billing](/concepts/wallet-billing.md)
- [API authentication: session tokens and API keys](/api-reference/authentication.md)