balance.low

POSTyour webhook address

Balance is low. The available balance (the balance minus the reserves of messages and campaigns in progress) fell below the threshold of the account. Top it up in the console to keep sending.

Body

Field	Type	Description
type	string	Always balance.low.
timestamp	string (date-time)	When the event happened, UTC.
data	object
data.available	object	The available balance now.
data.available.amount	string	A decimal with 6 digits after the point.
data.available.currency	string	ISO 4217 code of the account currency.
data.threshold	object	The low balance threshold of the account.
data.threshold.amount	string	A decimal with 6 digits after the point.
data.threshold.currency	string	ISO 4217 code of the account currency.

{
  "type": "balance.low",
  "timestamp": "2026-11-02T12:00:04+00:00",
  "data": {
    "available": {
      "amount": "4.200000",
      "currency": "USD"
    },
    "threshold": {
      "amount": "5.000000",
      "currency": "USD"
    }
  }
}

Headers

Header	Description
webhook-id	The delivery, whd_…. The same on every attempt of one delivery: use it to drop a repeated delivery.
webhook-timestamp	Unix time of the attempt, in seconds. Refuse deliveries older than 5 minutes.
webhook-signature	v1, and the base64 HMAC-SHA256 of {webhook-id}.{webhook-timestamp}.{body}, keyed with the secret (the part after whsec_, base64-decoded).
content-type	application/json
user-agent	ACE-SEND-Webhooks/1

Check the signature before you trust the body, answer 2xx within 5 seconds and do the work afterwards. See Webhooks for the signature check, retries and duplicates.