# Set or remove the monthly spend limit and alert thresholds

Source: https://joinsimplesms.com/docs/api/spend-limit/update
Index: https://joinsimplesms.com/llms.txt

`PATCH /v1/spend-limit`

Live outbound messages that would exceed the cap are rejected with 403 spend_limit_reached and not charged. Thresholds fire spend.threshold_reached once each per month. Scope: billing.

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.

## Request body

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

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `monthly_limit_usd` | number | No | null removes the cap Maximum 1000000. Minimum 1. Nullable. |
| `alert_thresholds` | array of integer | No | At most 5 items. |

## Responses

| Status | Meaning | Body |
| --- | --- | --- |
| 200 | Updated spend limit | `SpendLimit` |
| 400 | Invalid request | `Error` |
| 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` |
| 429 | Rate limit or quota exceeded | `Error` |

### 200: `SpendLimit` fields

| Field | Type | Description |
| --- | --- | --- |
| `object` | `spend_limit` |  |
| `monthly_limit_usd` | number | Nullable. |
| `alert_thresholds` | array of integer |  |
| `applies_to` | array of `outbound_sms` |  |
| `estimated_cost_per_message_usd` | number |  |
| `current_month` | object |  |
| `current_month.month` | string | Example: `2026-10`. |
| `current_month.spent_usd` | number |  |
| `current_month.remaining_usd` | number | Nullable. |
| `updated_at` | string (date-time) | Nullable. |

## Errors

| Status | When |
| --- | --- |
| 400 | Invalid request |
| 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 |
| 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"
  }
}
```

## Examples

### curl

```bash
curl -X PATCH "https://api.joinsimplesms.com/v1/spend-limit" \
  -H "Authorization: Bearer $SIMPLESMS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "alert_thresholds": [
    50,
    80,
    100
  ]
}'
```

### Node.js

The Node.js SDK does not wrap this endpoint yet; call it with `fetch`.

```javascript
const res = await fetch('https://api.joinsimplesms.com/v1/spend-limit', {
  method: 'PATCH',
  headers: {
    Authorization: `Bearer ${process.env.SIMPLESMS_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "alert_thresholds": [
      50,
      80,
      100
    ]
  }),
});

if (!res.ok) throw new Error((await res.json()).error.message);
const data = await res.json();
```

### Python

The Python SDK does not wrap this endpoint yet; call it over HTTP.

```python
import json, os, urllib.request

req = urllib.request.Request(
    "https://api.joinsimplesms.com/v1/spend-limit",
    method="PATCH",
    headers={
        "Authorization": f"Bearer {os.environ['SIMPLESMS_API_KEY']}",
        "Content-Type": "application/json",
    },
    data=json.dumps({
        "alert_thresholds": [
            50,
            80,
            100
        ]
    }).encode(),
)
with urllib.request.urlopen(req) as res:
    data = json.load(res)
```

## Related

- Guide: [Spend limits](/docs/spend-limits)
- [All spend limit endpoints](/docs/api#spend-limit)
- [API reference](/docs/api)