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How to prepare a file to import?
How to prepare a file to import?
Ilona Srebnicka avatar
Written by Ilona Srebnicka
Updated over a week ago

You probably already have a database of contacts stored on your e-commerce platform, in a marketing tool you've used in the past or even in a simple spreadsheet.

By downloading the contact database, you will get a spreadsheet containing at least a column of email addresses. There is no limit to the number of contacts you can have in your database.

Export your current customer database and prepare it according to the instructions below.

Once you have structured your spreadsheet, you will need to save it as a file in .csv, .xls or .xlsx format. Only these file formats are supported by us.

If you save the file as a CSV (our recommended format) make sure that the file's columns are separated by semicolons ( or commas) and make sure that the file is saved in the UTF-8 encoding system.

Also, don't use special characters (such as periods) in the file name.

CSV file example:

Opening a file using LibreOffice as an example:

Formatting the file

Below is a table showing the mandatory and optional fields to be filled in the CSV file and how to fill in and format each column.


Method of completion and formatting

email (mandatory)

email address






numbers only (white spaces and dialing numbers are acceptable)


M (for men)

F (for women)


NIEZNANY (for unknown)

INNY (for other)

birth date

RRRR-MM-DD (date format required)






in accordance with ISO 639-1 code

two lowercase letters, e.g. en for English speakers

email subscription status (mandatory when from file)

1 for subscribers

0 for unsubscribed

empty field for unknown status

sms subscription status

1 for subscribers

0 for unsubscribed

empty field for unknown status


text - if you want to assign multiple tags, separate them with commas

date of email subscription confirmation

RRRR-MM-DD (date format required)

This is how a sample file properly prepared for import looks like:

XLS and XLSX files

If you save a file in XLS or XLSX format and decide to import files in either of these formats, you must remember that no column or row can be left blank. If any column or row is left empty you will see an error and your import will fail.

Best practices for formatting the database

  • Enter the first and last name in separate columns. This will allow you to send personalized messages using only the person's first name ("Hi, Mary!") instead of the full name ("Hi, Mary Smith!").

  • Remove from the file all columns that will not be imported into your CRM (e.g., address, social security number).

  • Remove all duplicates. During import, our system will automatically detect duplicate emails and ignore them, so this is not required. However, it helps to keep your files as light as possible.

Do you need additional help?

If you have any additional questions about preparing your file for import, please contact us at

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