type is required and must be a known template type.type = folders and subType = custom.data.id and pass it as folderIds on segments.FOLDER_LIMIT_EXCEEDED when the workspace already has 500 folders.curl --location 'https://app.highperformr.ai/api/templates' \
--header 'x-api-key: <api-key>' \
--header 'Content-Type: application/json' \
--data '{
"name": "Q3 outbound",
"type": "folders",
"subType": "custom",
"description": "Campaign audiences for Q3"
}'{
"data": {
"id": "folder_abc123",
"type": "templates",
"attributes": {
"name": "Q3 outbound",
"description": "Campaign audiences for Q3",
"type": "folders",
"subType": "custom",
"isDefault": false,
"createdAt": "2026-09-24T07:00:00.000Z"
}
}
}