email.complained
Fires when an email was delivered but the recipient marked it as spam.
The email.complained event fires when an email was successfully delivered, but the recipient marked it as spam. Complaints are a strong negative signal for your sender reputation.
MailBlastr adds the complaining address to your account suppression list so future sends to it are skipped automatically.
{
"type": "email.complained",
"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"
}
}
}typestringoptionalThe event type that triggered the webhook.
created_atstringoptionalISO 8601 timestamp when the webhook event was created.
dataobjectoptionalEvent-specific data. The fields below live inside this object.
data.campaign_idstringoptionalIdentifier for the campaign, if applicable.
data.created_atstringoptionalISO 8601 timestamp when the email was created.
data.email_idstringoptionalUnique identifier for this email.
data.message_idstringoptionalRFC Message-ID header value for the email.
data.fromstringoptionalSender address; may include a display name.
data.tostring[]optionalRecipient email address(es).
data.subjectstringoptionalEmail subject line.
data.template_idstringoptionalIdentifier of the template used, if applicable.
data.tagsobjectoptionalObject of tag key-value pairs associated with the email.