Bulk Validate a Lead List From a Excel workbook Using Mails.so

The Scenario

You've been managing demand gen for the past quarter and you have 20,000 new leads sitting in an Excel workbook — collected from paid ads, a content download, and a partner co-marketing push. Before any of them go into Salesforce, your ops team wants them validated. Not a sample. All of them.

The bad version:

• Break the list into batches of 1,000 because the dashboard has an upload cap, then submit each batch separately and track which job ID belongs to which slice
• Poll the Mails.so dashboard every 20 minutes waiting for each batch to complete, download the result files as they finish, and reassemble them in the right order
• Import the consolidated results file and use INDEX-MATCH to merge statuses back into the original workbook before handing it off to ops

Twenty thousand rows is not a one-afternoon job when you're doing it manually. And ops is waiting on this before they run the Salesforce import — which is already a day behind because you were waiting on the list to be ready in the first place.

The Easy Way: One Prompt in SheetXAI

SheetXAI is an AI agent that lives inside your Excel workbook. It reads the full list, submits it to Mails.so as a bulk validation batch through the built-in integration, and writes the results back once the job completes — without you managing job IDs, polling, or reassembly.

Submit all emails in column B as a bulk validation batch to Mails.so and when the job completes write the validation status for each email into column C.

What You Get

• SheetXAI submits the full email column as a bulk batch to the Mails.so API
• Column C fills with the validation status for each row once the job finishes: valid, invalid, or risky
• Rows where the batch result has no match are written with no result so gaps are visible
• The row order in your workbook is preserved — results write back to the originating row

What If the Data Is Not Quite Ready

The email column has duplicates and you don't want to pay to validate the same address twice

Deduplicate the emails in column B before submitting the bulk validation batch to Mails.so. Write the validation result into column C for every row, reusing the result for any duplicate addresses.

Some rows are missing an email address entirely

Submit all non-empty emails in column B as a bulk validation batch to Mails.so. Write the result into column C for each row that had an email. Write "no email" in column C for any row where column B was blank.

You need to write REMOVE in column D for any email that comes back invalid

Bulk-validate the email list in column B with Mails.so, retrieve the batch results, and write REMOVE in column D for any email that comes back invalid. Leave column D blank for valid or risky addresses.

Validate, flag for removal, and write the failure reason in one pass

Bulk-validate all emails in column B with Mails.so. Write the status into column C, write REMOVE in column D for invalid addresses, and write the specific failure reason into column E for any address that is invalid or risky. Leave columns D and E blank for valid addresses.

One prompt does the validation, the suppression flag, and the failure annotation without chaining separate steps.

Try It

Get the 7-day free trial of SheetXAI and open your lead list workbook, then ask it to submit the email column as a bulk batch and write the results back. See also how to validate emails before a campaign or review the full Mails.so integration overview.