Which events are supported by webhooks?

Webhooks allow real-time event tracking across all supported message statuses, including specific delivery, error, and Event Flow events. Webhooks are designed to integrate seamlessly with external systems and offer full transparency of message handling from submission to final delivery or failure.

In this article you will learn more about:

Supported Events
Response

Supported Events

Webhooks support all standard SendPro message events, including a few that are unique to Webhooks such as Delivered and Event Flow-related events.

Note

The events Processed, Submitted and Delivered have a different JSON structure. Click on the specific event for more information and an example.

SOFTBOUNCE

Message has received a soft bounce

HARDBOUNCE

Message has received a hard bounce

COMPLAINT

Message has received a complaint (feedback loop)

REJECT

Message is rejected (due to being on the filter list)

DISCARD

Message is discarded (due to discard flowstep)

DELIVERED

Message has been delivered (accepted by receiving system)
The DELIVERED from the Webhooks has no equivalent in the Api and has a different JSON structure than most other responses, see an example below

[
  {
    "messageEvent": {
      "id": "ba1bfcc2-67a3-4e28-a8b9-c2b(...)",
      "messageId": "2025081814(...)",
      "type": "DELIVERED",
      "received": "2025-08-18T14:19:59.514Z",
      "inserted": "2025-08-18T14:19:59.668Z",
      "snippet": "250 2.0.0 Ok: queued as 7B60551CD8\r\n",
      "mta": "(...)flowmailer.net [185.136(...)]",
      "data": null,
      "extraData": {
        "vmta": {
          "hostname": "(...)flowmailer.net"
        },
        "connectionId": "2777(...)",
        "tls": {
          "cipher": "TLS(...)",
          "protocol": "TLS(...)"
        },
        "mx": {
          "expanded": "(...)flowmailer.net",
          "original": "(...)flowmailer.net",
          "address": "185.136(...)"
        }
      }
    },
    "messageTags": []
  }
]

POSTED

SMS or Letter has been sent

ATTEMPT

Delivery has been attempted, and will be retried

SUBMITTED

Message has been accepted by SendPro

Submitted events use the following structure (adding the message object). If your system has difficulty processing these differences, you can set up a separete webhook for Submitted using Filters.

 {
    "message": {
      "submitted": "2025-08-18T14:19:00.000Z",
      "id": "202508(...)",
      "transactionId": "97a4(...)",
      "messageIdHeader": null,
      "messageType": "EMAIL",
      "source": {
        "id": "7(...)",
        "description": "Test source"
      },
      "flow": {
        "id": "19043",
        "description": "Test flow"
      },
      "senderAddress": "example@(...).nl",
      "recipientAddress": "(...)@spotler.com",
      "backendStart": "2025-08-18T14:19:00.290Z",
      "backendDone": null,
      "headersIn": [
        {
          "name": "Received",
          "value": "from 10.254.11.4   by  (Flowmailer API) with HTTPS ID cbc483a(...) for <(...)@spotler.com>;   Mon, 18 Aug 2025 16:19:00 +0200 (CEST)"
        },
        {
          "name": "MIME-Version",
          "value": "1.0"
        },
        {
          "name": "From",
          "value": "Your name "
        },
        {
          "name": "To",
          "value": "Your name <(...)@spotler.com>"
        },
        {
          "name": "Subject",
          "value": "Example test"
        },
        {
          "name": "Content-Type",
          "value": "text/plain; charset=UTF-8"
        },
        {
          "name": "Content-Transfer-Encoding",
          "value": "quoted-printable"
        }
      ],
      "status": "SUBMITTED",
      "subject": "Example test",
      "from": "example@(...).nl",
      "events": null,
      "fromAddress": {
        "name": "Your name",
        "address": "example@(...).nl"
      },
      "toAddressList": [
        {
          "name": "Your name",
          "address": "(...)@spotler.com"
        }
      ],
      "tags": [
        "MyEarlytag"
      ]
    },
    "messageEvent": {
      "id": "202508(...)",
      "messageId": "202508(...)",
      "type": "SUBMITTED",
      "received": "2025-08-18T14:19:00.281Z",
      "inserted": null,
      "snippet": null,
      "mta": null,
      "data": null
    },
    "messageTags": [
      "MyEarlytag",
      "thisisatag"
    ]
  }

PROCESSED

Message is being handled by SendPro

Processed events use the following structure (adding the message object). If your system has difficulty processing these differences, you can set up a separete webhook for Processed using Filters.

 {
    "message": {
      "submitted": "2025-08-18T14:19:00.000Z",
      "id": "20250818141(...)",
      "transactionId": "97a4d6c277a(...)",
      "messageIdHeader": "<(...).flowmailer.net>",
      "messageType": "EMAIL",
      "source": {
        "id": "70(...)",
        "description": "Postman test Api"
      },
      "flow": {
        "id": "19(...)",
        "description": "Example flow"
      },
      "senderAddress": "example@(...).nl",
      "recipientAddress": "(...)@spotler.com",
      "backendStart": "2025-08-18T14:19:00.290Z",
      "backendDone": "2025-08-18T14:19:00.623Z",
      "headersIn": [
        {
          "name": "Received",
          "value": "from 10.254.11.4   by  (Flowmailer API) with HTTPS ID cbc483adb6a(...)5   for <(...)@spotler.com>;   Mon, 18 Aug 2025 16:19:00 +0200 (CEST)"
        },
        {
          "name": "MIME-Version",
          "value": "1.0"
        },
        {
          "name": "From",
          "value": "Your name "
        },
        {
          "name": "To",
          "value": "Your name <(...)@spotler.com>"
        },
        {
          "name": "Subject",
          "value": "Example test"
        },
        {
          "name": "Content-Type",
          "value": "text/plain; charset=UTF-8"
        },
        {
          "name": "Content-Transfer-Encoding",
          "value": "quoted-printable"
        }
      ],
      "headersOut": [
        {
          "name": "MIME-Version",
          "value": "1.0"
        },
        {
          "name": "From",
          "value": "Your name "
        },
        {
          "name": "To",
          "value": "Your name <(...)@spotler.com>"
        },
        {
          "name": "Subject",
          "value": "Example test"
        },
        {
          "name": "Content-Type",
          "value": "text/html; charset=UTF-8"
        },
        {
          "name": "Content-Transfer-Encoding",
          "value": "quoted-printable"
        },
        {
          "name": "Feedback-ID",
          "value": "543:543-(...):flowmailer"
        },
        {
          "name": "Message-ID",
          "value": "<20250(...)@(...).net>"
        },
        {
          "name": "Date",
          "value": "Mon, 18 Aug 2025 14:19:00 +0000"
        },
        {
          "name": "X-Job",
          "value": "fm-7037-19043"
        }
      ],
      "status": "PROCESSED",
      "subject": "Example test",
      "from": "example@(...).nl",
      "events": null,
      "fromAddress": {
        "name": "Your name",
        "address": "example@(...).nl"
      },
      "toAddressList": [
        {
          "name": "Your name",
          "address": "(...)@spotler.com"
        }
      ],
      "tags": [
        "MyEarlytag",
        "thisisatag"
      ]
    },
    "messageEvent": {
      "id": "42d71b39-57(...)",
      "messageId": "202508(...)",
      "type": "PROCESSED",
      "received": "2025-08-18T14:19:00.623Z",
      "inserted": null,
      "snippet": null,
      "mta": null,
      "data": null,
      "extraData": {
        "totalProcessingTimeMillis": 309
      }
    },
    "messageTags": [
      "MyEarlytag",
      "thisisatag"
    ]
  }

OPENED

Message has been opened (tracking pixel has loaded)

CLICKED

Link in message has been clicked (tracking link has been activated)

HELD

Message is on Held list, likely due to error

CUSTOM

Message has custom event

REPLY

Message sent to return path

RESENT

Message has been resent from API or UI

SUSPENDED

Message on hold, due to scheduling

RESUBMITTED

Message has been resubmitted (resubmit flowstep)

ERROR

Message cannot be handled due to error

RESUMED

Previous error has been resumed

EVENT_PROCESSED

Message in Event Flow is being handled by SendPro

EVENT_INSERTED

Message in Event Flow has been accepted by SendPro

EVENT_SUSPENDED

Message in Event Flow on hold, due to scheduling

EVENT_ERROR

Message in Event Flow cannot be handled due to error

EVENT_RESUMED

Error in Event Flow has been resumed

EVENT_DISCARD

Message in Event Flow is discarded (due to discard flowstep)

Response

Webhook responses follow the same JSON format as the Spotler SendPro API. The Inserted status in the API is renamed to Submitted in Webhooks to match better with what you will see in the Dashboard.

Basic Structure

Webhook events can have up to three possible object types:

messageEvent, containing info about the event(s)
message, containing information about the message sent - used in processed and submitted events
messageTags, containing the tags for a message, if Add Message Tags is selected in the interface

Single Event

An event will always have a type (in this case CLICKED). In this example, Message tags are also added.

[
  {
    "messageEvent": {
      "id": "1fbbaa3d-0a95-4e5d-b266-a0(...)",
      "messageId": "202503181426(...)",
      "type": "CLICKED",
      "received": "2025-08-06T14:10:36.764Z",
      "inserted": "2025-08-06T14:10:36.815Z",
      "extraData": {
        "_mr": "false"
      },
      "referer": null,
      "remoteAddr": "178.224.132.(...)",
      "userAgentString": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:141.0) Gecko/20100101 Firefox/141.0",
      "deviceCategory": "Desktop",
      "userAgent": "Firefox",
      "userAgentType": "Browser",
      "userAgentVersion": null,
      "userAgentDisplayName": "Firefox",
      "operatingSystem": "Win10",
      "operatingSystemVersion": "10.0",
      "linkTarget": "https://web.flowmailer.net/viewonline.html?id=-4SLb9jkGGk:MRnxuS3q3qCq_(...)",
      "linkName": "https://web.flowmailer.net/viewonline.html?"
    },
    "messageTags": [
      "thisisatag"
    ]
  }
]

Multiple Events

A webhook may contain multiple events.

[ 
  {
    MessageEvent {...}
    MessageTags {...}
  },
  {
    MessageEvent {...}
    MessageTags {...}
  },  
  {
    message {...}
    MessageEvent {...}
    MessageTags {...}
  }
]

Event Flow Events

Event Flow events (such as EVENT_ERROR, EVENT_DISCARD) contain the triggering event.

[
  {
    "messageEvent": {
      "id": "f65b5ad5-cac5-46b5-9f76-6b(...)",
      "messageId": "20250318142607736(...)",
      "type": "EVENT_DISCARD",
      "received": "2025-08-06T14:10:42.625Z",
      "inserted": "2025-08-06T14:10:42.871Z",
      "snippet": "Discarded",
      "mta": null,
      "data": null,
      "extraData": {
        "eventFlow": {
          "event": {
            "received": "2025-08-06T14:10:42.310Z",
            "id": "236371d0-3804-45e5-af38-0a(...)",
            "type": "CLICKED"
          },
          "flow": {
            "id": 132655
          }
        }
      }
    },
    "messageTags": [
      "thisisatag"
    ]
  }
]

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