Bulk Email Verification: CSV Upload Guide

Bulk verification lets you upload a list of email addresses and verify them all at once. It's the fastest way to clean an entire mailing list.

Preparing Your CSV File

• Email addresses must be in the first column of your CSV file.
• A header row is optional — Mailthentic auto-detects it.
• The file should be in CSV format (.csv).
• There is no strict row limit, but larger files take proportionally longer to process.

Example CSV Format

email
john@example.com
jane@company.org
info@business.net

Uploading & Starting the Job

1. Navigate to Bulk Verification in your dashboard.
2. Click Upload CSV and select your file.
3. Mailthentic scans the file and shows a summary:
   • Total email addresses found
   • Duplicate addresses detected (automatically removed)
   • Credits required (1 per unique email)
4. Click Start Verification to begin.

Monitoring Progress

The job runs in the background. You can:

• Watch the progress bar on the job detail page (auto-refreshes every few seconds).
• Close the browser and come back later — your job will keep running.
• Check the Jobs page to see all active and completed jobs.

Downloading Results

When the job completes, you can download results in two formats:

• CSV — Universal format, works with any spreadsheet app.
• Excel (.xlsx) — Ready-to-use in Microsoft Excel with formatted columns.

The results file includes all original data plus verification columns: status, confidence score, MX provider, catch-all flag, and DNS security indicators.

Duplicate Handling

Mailthentic automatically detects duplicate email addresses in your upload. Duplicates are removed before processing, so you're only charged once per unique address.

Re-Verifying a Job

Email data goes stale over time. You can re-verify any completed job by clicking the Re-verify button on the job detail page. This creates a new job with the same email list.