# Send a verification code

Source: https://joinsimplesms.com/docs/api/verify/send-verification
Index: https://joinsimplesms.com/llms.txt

`POST /v1/verify`

Generates a one-time code, sends it, and enforces expiry, attempt limits and anti-pumping controls. You do NOT need to own a phone number; SimpleSMS sends from its own verification pool. Nothing is billed here; a verification is charged only when the code is checked successfully. Supports the Idempotency-Key header, so a retried request does not text a second code.

Send your API key as a bearer token: `Authorization: Bearer ssms_sk_...`. Test keys run this endpoint against the [sandbox](/docs/sandbox); see [Authentication](/docs/authentication) for key modes and scopes.

## Headers

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `Idempotency-Key` | string | No | Makes retries safe for 24 hours: the same key and body replays the original successful response (with Idempotent-Replayed: true); a different body returns 409. Failed requests release the key. At most 255 characters. |

## Request body

JSON (`Content-Type: application/json`).

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `phone` | string | Yes | Example: `+14155550132`. |
| `app_name` | string | No | Your product name, shown in the message At most 24 characters. |
| `from` | string | No | Optional: send from a number you own instead of the SimpleSMS pool |
| `customer_id` | string | No | Optional: attribute the verification to one of your customers |

## Responses

| Status | Meaning | Body |
| --- | --- | --- |
| 201 | Verification created | `Verification` |
| 401 | Missing, malformed, or revoked API key | `Error` |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged | `Error` |
| 403 | Blocked by Shield (charged: false) | `Error` |
| 409 | Idempotency conflict | `Error` |
| 429 | Rate limit or quota exceeded | `Error` |

### 201: `Verification` fields

| Field | Type | Description |
| --- | --- | --- |
| `id` | string | Example: `ver_a1B2c3D4e5F6g7H8`. |
| `object` | `verification` |  |
| `phone` | string |  |
| `status` | `pending`, `approved`, `expired`, `max_attempts`, `blocked` |  |
| `attempts` | integer |  |
| `test` | boolean |  |
| `charged` | boolean |  |
| `created_at` | string (date-time) |  |
| `expires_at` | string (date-time) |  |
| `customer_id` | string | The customer this is attributed to. Present only when set. |

## Errors

| Status | When |
| --- | --- |
| 401 | Missing, malformed, or revoked API key |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged |
| 403 | Blocked by Shield (charged: false) |
| 409 | Idempotency conflict |
| 429 | Rate limit or quota exceeded |

Every error has the same JSON shape, and `request_id` matches the `X-Request-Id` response header. [Errors](/docs/errors) lists every code and what to do about it.

```json
{
  "error": {
    "code": "invalid_request",
    "message": "What went wrong, in plain words.",
    "param": "the_field",
    "request_id": "req_a1B2c3D4e5F6g7H8"
  }
}
```

## Idempotency

Send an `Idempotency-Key` header to make retries safe. For 24 hours the same key with the same body replays the original successful response (with `Idempotent-Replayed: true`); the same key with a different body returns 409. A failed request releases its key.

## Examples

### curl

```bash
curl -X POST "https://api.joinsimplesms.com/v1/verify" \
  -H "Authorization: Bearer $SIMPLESMS_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 6f1c2f0e-order-1042" \
  -d '{
  "phone": "+14155550132"
}'
```

### Node.js

```javascript
import { SimpleSMS } from 'joinsimplesms'; // npm install joinsimplesms

const sms = new SimpleSMS(process.env.SIMPLESMS_API_KEY);

const verification = await sms.verify.send({ to: '+14155550132' });

console.log(verification.id, verification.status);
```

### Python

```python
import os
from joinsimplesms import SimpleSMS  # pip install joinsimplesms

client = SimpleSMS(os.environ["SIMPLESMS_API_KEY"])

verification = client.verify.send("+14155550132")

print(verification["id"], verification["status"])
```

## Related

- Guide: [Verify](/docs/verify)
- [All verify endpoints](/docs/api#verify)
- [API reference](/docs/api)