The EVENT_DELIVERY trigger fires when there's a delivery status update for an event your app sent to a contact. Events are non-message interactions such as composing indicators or typing notifications. This trigger works similarly to MESSAGE_DELIVERY but is specifically for events rather than messages.

When It Fires

Event successfully delivered to the channel
Event delivery failed
Event queued on the channel

Note: Most channels don't support app-initiated events, so this trigger is rarely used in practice. WhatsApp and RCS are the primary channels that support sending events from apps to contacts.

Callback Structure

The webhook callback contains an event_delivery_report object with these key fields:

Field	Type	Description
`event_id`	string	ID of the event this status update is for
`conversation_id`	string	Conversation the event belongs to
`status`	string	Delivery status (`DELIVERED`, `FAILED`, `QUEUED_ON_CHANNEL`)
`channel_identity`	object	Channel-specific recipient information
`contact_id`	string	Contact who should receive the event
`reason`	object	Error details (if status is `FAILED`)
`metadata`	string	Metadata attached to the original event

Status Values

Status	Description
`QUEUED_ON_CHANNEL`	Event submitted to channel, awaiting delivery
`DELIVERED`	Event delivered successfully
`FAILED`	Event delivery failed

Reason Object (for FAILED status)

Field	Type	Description
`code`	string	High-level error category
`description`	string	Human-readable error description
`sub_code`	string	Detailed error code

Common Use Cases

Event Tracking — Monitor delivery of composing indicators or typing events (rare use case)
Debugging Event Sending — Identify when events fail to deliver to specific channels
Channel Capability Testing — Determine which channels successfully support event delivery

Note: Since most apps don't send events (they send messages), this trigger is rarely needed. Most implementations only use MESSAGE_DELIVERY and ignore EVENT_DELIVERY.

Example Callback Payload

Success: Event Delivered

{
  "app_id": "01H1234567...",
  "accepted_time": "2024-06-15T14:30:45.456Z",
  "event_time": "2024-06-15T14:30:45.123Z",
  "project_id": "PROJECT123",
  "event_delivery_report": {
    "event_id": "01H9876543...",
    "conversation_id": "01H5555555...",
    "status": "DELIVERED",
    "channel_identity": {
      "channel": "WHATSAPP",
      "identity": "46732001122",
      "app_id": "01H1234567..."
    },
    "contact_id": "01H3333333...",
    "metadata": "",
    "processing_mode": "CONVERSATION"
  }
}

Failure: Unsupported on Channel

{
  "app_id": "01H1234567...",
  "accepted_time": "2024-06-15T14:31:00.789Z",
  "project_id": "PROJECT123",
  "event_delivery_report": {
    "event_id": "01H8888888...",
    "conversation_id": "01H5555555...",
    "status": "FAILED",
    "channel_identity": {
      "channel": "SMS",
      "identity": "15551234567",
      "app_id": "01H1234567..."
    },
    "contact_id": "01H3333333...",
    "reason": {
      "code": "UNSUPPORTED_CONTENT",
      "description": "SMS does not support sending events",
      "sub_code": "CHANNEL_LIMITATION"
    },
    "processing_mode": "CONVERSATION"
  }
}

Queued on Channel

{
  "app_id": "01H1234567...",
  "accepted_time": "2024-06-15T15:00:00.123Z",
  "project_id": "PROJECT123",
  "event_delivery_report": {
    "event_id": "01H7777777...",
    "conversation_id": "01H5555555...",
    "status": "QUEUED_ON_CHANNEL",
    "channel_identity": {
      "channel": "RCS",
      "identity": "15551234567",
      "app_id": "01H1234567..."
    },
    "contact_id": "01H3333333...",
    "metadata": "",
    "processing_mode": "CONVERSATION"
  }
}

Key Points

Rarely Used — Most apps never send events, only receive them via EVENT_INBOUND, making this trigger uncommon
Limited Channel Support — Only WhatsApp and RCS support app-initiated events; SMS, MMS, and most other channels don't
No Read Receipts — Unlike messages, events don't have a READ status; only DELIVERED or FAILED
Composing Indicators — The main use case is sending "agent is typing" indicators in customer service applications
Event Types — Currently, only composing/typing events can be sent by apps; other event types are receive-only
Lightweight — Events don't count against message quotas and aren't stored in conversation history
Optional Monitoring — You can safely ignore this trigger if your app doesn't send events; focus on MESSAGE_DELIVERY instead