Set or remove the monthly spend limit and alert thresholds

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; see 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 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)