curl --request POST \
  --url https://api.pocketflows.com/businesses/{id}/email_templates/embeds \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "expires_in": 123
}
'

{
  "id": "<string>",
  "expires_at": "<string>",
  "email_template": "<string>",
  "business": "<string>",
  "url": "<string>"
}