Bulk upload attributes. If an attribute already exists, it is replaced. This endpoints accepts either JSON or CSV form uploads. If there is an issue parsing any of the attributes, an error is thrown and attributes with issues are sent back with error messages. The maximum size for a CSV file is 1MB, and CSVs must be encoded as UTF-8. The Attribute ID must start with a letter followed by a combination of dashes(-), underscores(_), letters(a-z A-Z), or numbers(0-9).
Note: The hash parameter is not part of the URL.