Webhooks

email.sent

Fires when an email is accepted by MailBlastr and handed off for delivery to the recipient's mail server.

The email.sent event fires whenever the API request to send an email was successful. MailBlastr has accepted the message and will attempt to deliver it to the recipient's mail server — a successful delivery is later reported by `email.delivered`.

Every payload follows the shared envelope: a top-level type, created_at, and a data object with the event-specific fields.

{
  "type": "email.sent",
  "created_at": "2026-06-22T23:41:12.126Z",
  "data": {
    "campaign_id": "8b146471-e88e-4322-86af-016cd36fd216",
    "created_at": "2026-06-22T23:41:11.894719+00:00",
    "email_id": "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794",
    "message_id": "<111-222-333@email.example.com>",
    "from": "Acme <onboarding@example.com>",
    "to": ["recipient@example.com"],
    "subject": "Sending this example",
    "template_id": "43f68331-0622-4e15-8202-246a0388854b",
    "tags": {
      "category": "confirm_email"
    }
  }
}

Payload

typestringoptional

The event type that triggered the webhook.

created_atstringoptional

ISO 8601 timestamp when the webhook event was created.

dataobjectoptional

Event-specific data. The fields below live inside this object.

data.campaign_idstringoptional

Identifier for the campaign, if the email was sent as part of one.

data.created_atstringoptional

ISO 8601 timestamp when the email was created.

data.email_idstringoptional

Unique identifier for this email.

data.message_idstringoptional

RFC Message-ID header value for the email.

data.fromstringoptional

Sender address as passed at send time; may include a display name (e.g. Name <email@example.com>).

data.tostring[]optional

Recipient email address(es).

data.subjectstringoptional

Email subject line.

data.template_idstringoptional

Identifier of the template used, if applicable.

data.tagsobjectoptional

Object of tag key-value pairs associated with the email.

This is one of several events MailBlastr can deliver. See the full list of webhook event types.