Can SendGrid webhook events include custom_args from personalizations? - sendgrid

Question

I'm using a dynamic template in SendGrid to send transactional emails that typically go to multiple recipients in the personalizations field. The message body includes custom_args that are shared among all recipients, and in personalizations, both custom_args and dynamic_template_data specific to each recipient. Webhook events return the shared custom_args, but none of the recipient-specific custom_args. Is there a way to get events together with the personalized custom_args? Here's an example request body where we add a userId custom_arg for each recipient:
{
"from": {
"email": "sender#example.com",
"name": "Example Sender"
},
"personalizations": [
{
"to": [
{
"email": "recipient1#example.com",
"custom_args": {
"userId": "63r20acm4xfv"
}
}
],
"dynamic_template_data": {
"subject": "New Article",
"description": "Read the lastest news on...",
"documentId": "624dxnpvhw8g",
"host": "https://localhost:8000",
"userId": "63r20acm4xfv"
}
}
],
"custom_args": {
"documentId": "624dxnpvhw8g"
}
}
And the webhook events we receive (the "documentId" custom arg is reported, but not the "userID" custom_arg from personalizations):
[
{
"documentId": "624dxnpvhw8g",
"email": "recipient1#example.com",
"event": "processed",
"sg_event_id": "cHJvY2Vzc2VkLTI3MTk3NzMzLUtTUEJOaVpGUXpXb05KblctVDBNRkEtMA",
"sg_message_id": "KSPBNiZFQzWoNJnW-T0MFA.filterdrecv-58c58fcb9f-44vrp-1-6312139C-1F6.0",
"sg_template_id": "d-1ebc6b474b7041c0b439d1bdb17650e4",
"sg_template_name": "DEFAULT TEMPLATE",
"smtp-id": "<redacted>",
"timestamp": 1662128000
},
{
"documentId": "624dxnpvhw8g",
"email": "recipient1#example.com",
"event": "delivered",
"ip": "<redacted>",
"response": "250 Message received",
"sg_event_id": "ZGVsaXZlcmVkLTAtMjcxOTc3MzMtS1NQQk5pWkZReldvTkpuVy1UME1GQS0w",
"sg_message_id": "KSPBNiZFQzWoNJnW-T0MFA.filterdrecv-58c58fcb9f-44vrp-1-6312139C-1F6.0",
"sg_template_id": "d-1ebc6b474b7041c0b439d1bdb17650e4",
"sg_template_name": "DEFAULT TEMPLATE",
"smtp-id": "<redacted>",
"timestamp": 1662128002,
"tls": 1
}
]

Answer 1

Ugh - the custom_args in personalizations was at the wrong level. After moving the custom_args up to the same level as the dynamic_template_data, it worked fine and the values are included in the webhook events.
The example from the question was changed to:
{
"from": {
"email": "sender#example.com",
"name": "Example Sender"
},
"personalizations": [
{
"to": [
{
"email": "recipient1#example.com",
}
],
"custom_args": {
"userId": "63r20acm4xfv"
}
"dynamic_template_data": {
"subject": "New Article",
"description": "Read the lastest news on...",
"documentId": "624dxnpvhw8g",
"host": "https://localhost:8000",
"userId": "63r20acm4xfv"
}
}
],
"custom_args": {
"documentId": "624dxnpvhw8g"
}
}