Hi @Anthony - Please follow the below json format for adaptive card in webhook.
{
"type":"message",
"attachments":[
{
"contentType":"application/vnd.microsoft.card.adaptive",
"contentUrl":null,
"content":{
"$schema":"http://adaptivecards.io/schemas/adaptive-card.json",
"type":"AdaptiveCard",
"version":"1.2",
"body":[
{
"type": "TextBlock",
"text": "For Samples and Templates, see [https://adaptivecards.io/samples](https://adaptivecards.io/samples)"
},
{
"type": "Image",
"url": "https://adaptivecards.io/content/cats/1.png"
}
]
}
}
]
}