How to prepare a file to import it via FTP? MAX

It’s important you use this checklist to ensure your file uploads properly via FTP. If there are any formatting issues, individual rows can be skipped. In some cases, an entire file won’t upload.

File formatting requirements

File name
The file needs to have the same title as the tech name of your list. You can find the tech name in the settings of the list right below its name. It is a string of letters and numbers that looks like this: 89fc19d6e97656d57an88913ea07c95a – so using this example, the name of the file would be 89fc19d6e97656d57an88913ea07c95a.csv.

tech file name in list settings

File format
When getting the file ready for import, be sure to:

  • use a .CSV file,
  • use the UTF-8 encoding,
  • include headers in the file (otherwise, the file will be skipped),
  • be sure each column has a header (if a row has more fields than the header, the row will be skipped),
  • use commas (not semicolons) to separate the columns.

You should also keep in mind that:

  • BOM character is allowed at the beginning of the file,
  • multiline values are NOT supported,
  • both CRLF and LF line endings are accepted,
  • leading and trailing white spaces are trimmed from every field, including the header.

Formatting columns

Here are the things to remember when formatting columns:


  • email is a required field,
  • one email address per column,
  • double-check if the address is correct. An incorrect email will result in a skipped row.


  • use one name per column (you can use first_name and last_name columns, but you won’t be able to use them with the Name field)
  • Names can be max. 128 characters long (incorrect names aren’t stored).
  • Name is not a required field. If there’s no name column or value is empty, the existing contact name won’t be affected in any way.
  • A new name overwrites the existing contact name.

Subscription IP address

  • There has to be one subscription IP per line.
  • We support IPv4 dotted-decimal notation (like We won’t store incorrect values.
  • A missing column or an empty value won’t affect the existing contact IP address.
  • We assign GeoIP based on this IP address giving access to features like Perfect Timing.

Custom fields

  • All values other than name, email, and subscription IP address are treated as custom fields.
  • A custom field name can include lowercase English alphabet, numbers and underscores ‘_’. It can be max. 128 characters.
  • The maximum length for a custom field value is 255 characters. The value must be compatible with the user custom definition if such is present. We won’t store incorrect names or values.
  • A missing column or empty value won’t affect the custom values of existing contacts.
  • The value NULL will remove the custom field of existing contacts.