email.delivery_delayed

{
  "type": "email.delivery_delayed",
  "created_at": "2026-02-22T23:41:12.126Z",
  "data": {
    "broadcast_id": "8b146471-e88e-4322-86af-016cd36fd216",
    "created_at": "2026-02-22T23:41:11.894Z",
    "email_id": "56761188-7520-42d8-8898-ff6fc54ce618",
    "message_id": "<111-222-333@email.example.com>",
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Sending this example",
    "template_id": "43f68331-0622-4e15-8202-246a0388854b",
    "tags": {
      "category": "confirm_email"
    }
  }
}

Event triggered whenever the email couldn’t be delivered due to a temporary issue. Delivery delays can occur, for example, when the recipient’s inbox is full, or when the receiving email server experiences a transient issue.

Response Body Parameters

All webhook payloads follow a consistent top-level structure with event-specific data nested within the data object.

string

The event type that triggered the webhook (e.g., email.delivery_delayed).

string

ISO 8601 timestamp when the webhook event was created.

object

Event-specific data containing detailed information about the event. The data object for the email.delivery_delayed event contains the following parameters:

Hide object parameters

string

Unique identifier for the broadcast campaign (if applicable)

string

ISO 8601 timestamp when the email was created

string

Unique identifier for the specific email

string

RFC Message-ID header value for the email. Not included on email.scheduled, email.failed and email.suppressed events, because the email has not been sent when they fire

string

Sender’s email address. For sent events, this matches the value passed at send time and may include a display name (e.g., Name <email@domain.com>). For received events, this is the bare email address only; the display name from the original From: header is preserved in headers.from on the retrieve endpoint.

array

Array of impacted recipient email addresses

string

Email subject line

string

Unique identifier for the template used (if applicable)

Record<string, string>

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

{
  "category": "welcome",
  "user_id": "1234567890"
}

{
  "type": "email.delivery_delayed",
  "created_at": "2026-02-22T23:41:12.126Z",
  "data": {
    "broadcast_id": "8b146471-e88e-4322-86af-016cd36fd216",
    "created_at": "2026-02-22T23:41:11.894Z",
    "email_id": "56761188-7520-42d8-8898-ff6fc54ce618",
    "message_id": "<111-222-333@email.example.com>",
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Sending this example",
    "template_id": "43f68331-0622-4e15-8202-246a0388854b",
    "tags": {
      "category": "confirm_email"
    }
  }
}

⌘I

{
  "type": "email.delivery_delayed",
  "created_at": "2026-02-22T23:41:12.126Z",
  "data": {
    "broadcast_id": "8b146471-e88e-4322-86af-016cd36fd216",
    "created_at": "2026-02-22T23:41:11.894Z",
    "email_id": "56761188-7520-42d8-8898-ff6fc54ce618",
    "message_id": "<111-222-333@email.example.com>",
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Sending this example",
    "template_id": "43f68331-0622-4e15-8202-246a0388854b",
    "tags": {
      "category": "confirm_email"
    }
  }
}

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email.delivery_delayed

Response Body Parameters