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Last updated September 10, 2026

Uploading & Validating Lists

Validating large email lists is straightforward with MailInsightX.

Supported Formats

We support these file formats for bulk uploads:

  • .csv (Comma Separated Values)
  • .xls / .xlsx (Excel)
  • .txt (Plain Text, one email per line)

Make sure your file contains an explicit column named email (case-insensitive) if you are uploading a CSV/Excel file, or ensure the file contains one valid email per line for .txt.

Truncation and Limits

Your plan determines the maximum number of rows per upload. See Understanding Plan Tiers & Limits for the full, current table.

Tip

Automatic Truncation If you upload a file that exceeds your plan's limit, we will not block the upload or throw an error. MailInsightX will gracefully accept the file and automatically truncate the list to match your maximum limit - only the emails within your limit are extracted, charged, and validated.

Exporting Results

Once a job has finished processing, you can download the results from the Validator tab in your Dashboard.

MailInsightX never destroys your original data. When you export, we append Email, Verification Result, Category, and Score columns to the end of your original file/columns, so you never lose your custom IDs, names, or other metadata.