How do I format my CSV file correctly?

Updated Nov 2, 2026

Follow these rules so every row is imported.

File

  • A .csv file of up to 10 MB, with values separated by commas. Semicolon-separated files are not supported.
  • UTF-8 is recommended; the importer detects other encodings automatically.

Rows and columns

  • The first row must be a header row with your column names. It is never imported.
  • One contact per row, with an email address in every row.
  • Only the first 10 columns can be mapped. Put the columns you need first.
  • Values that contain commas must be wrapped in double quotes, for example "Acme, Inc.". Avoid line breaks inside values.
  • Each email address once. Duplicates are skipped.

Example

  • FirstName,LastName,Email,Company,Title
  • Ana,Pérez,ana@example.com,Acme,CEO

Related articles

Didn't find what you need?

Sign in to MailRush.io and open a support ticket, and our support team will get back to you.

Contact support