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Unknown

Unknown callbacks are triggered when an email's delivery has not been confirmed within one hour of sending it. The email's status is set to unknown. If the delivery outcome is confirmed later, a Delivered or Send Failed callback is still sent.

Unknown Webhook Payload

Parameter	Type	Required	Description	Example
`channel`	`string`	`true`	Always `email`	`email`
`event_type`	`string`	`true`	Always `email_unknown`	`email_unknown`
`batch_id`	`string`	`true`	UUID auto-generated per API send request and returned in the send response. Shared across all recipients (to, cc, bcc) of that single send.	`550e8400-e29b-41d4-a716-446655440000`
`message_id`	`string`	`true`	Internal identifier for the individual recipient record	`507f1f77bcf86cd799439011`
`tag`	`string`	`false`	Custom tag sent with the email	`welcome-email`
`bulk_tag`	`string`	`false`	User-provided string for grouping multiple sends across separate API calls	`campaign-april`
`event_meta`	`object`	`true`	Event-specific metadata
`event_meta.to`	`string`	`true`	Recipient email address	`[email protected]`
`event_meta.from`	`string`	`true`	Sender email address	`[email protected]`
`event_meta.reply_to`	`string`	`true`	Reply-to address	`[email protected]`
`event_meta.status`	`string`	`true`	Always `unknown`	`unknown`
`event_meta.sent_at`	`string`	`true`	Timestamp the email was sent in ISO 8601 format	`2024-01-15T10:30:00Z`
`event_meta.error`	`number`	`true`	Always `0` for unknown events	`0`

Unknown Webhook Payload