Spot-Check High-Priority Prospect Emails in a Excel workbook With Mails.so

The Scenario

A colleague dropped a workbook on your desk Monday morning — 200 email addresses, high-priority prospects, all sourced from LinkedIn and a conference badge scan. Your manager's note at the top of the email: "These are warm. Verify before you reach out. Don't waste them on bounces."

You've been in SDR for two years and you know what "warm" means: someone has already had contact with the company. Which also means a bounce here isn't just a bad metric — it's a bad impression on a prospect who's already in the funnel.

The bad version:

• Copy the email list into the Mails.so dashboard and upload it as a batch, then wait for results and download the output file
• Cross-reference 200 rows by hand to find which ones have no MX record or are flagged disposable, then mark them in the original workbook
• Decide row by row which flagged addresses are worth a manual follow-up and which should be pulled from the sequence entirely

Two hundred rows is small enough that the process feels manageable — until you realize it's going to take an hour you don't have, and the sequence starts Thursday.

The Easy Way: One Prompt in SheetXAI

SheetXAI is an AI agent that lives inside your Excel workbook. It reads the prospect list, runs each email through Mails.so one by one through the built-in integration, and writes the detailed validation results back directly — so you can see exactly which addresses are risky and why, before you invest a single outreach touch.

For each email in column A, run a single Mails.so validation and write the full result including is_disposable, mx_found, and overall status into columns B, C, and D respectively.

What You Get

• Column B fills with the is_disposable value for each email: true or false
• Column C fills with the mx_found value: true or false
• Column D fills with the overall Mails.so status: valid, invalid, or risky
• Any row where the API returns an error gets check manually in column D so nothing disappears silently

What If the Data Is Not Quite Ready

Some addresses are formatted with display names — "First Last email@domain.com" — and the API won't accept that format

For each row in column A, extract just the email address from the value before sending it to Mails.so. Validate the extracted address and write is_disposable into column B, mx_found into column C, and the overall status into column D.

You want rows with no MX record highlighted in red so they stand out in the review

Validate all emails in column A with Mails.so one by one. Write is_disposable into column B, mx_found into column C, and the overall status into column D. Highlight any row red where mx_found is false or where the status is invalid.

A second worksheet called "Backup Contacts" has additional emails you want to validate with the same logic

Validate all emails in column A on the current worksheet with Mails.so and write the three fields into columns B, C, and D. Then do the same for all emails in column A on the worksheet named Backup Contacts.

Validate, flag high-risk rows, and write a recommended action in one pass

For each email in column A, validate with Mails.so and write is_disposable into column B, mx_found into column C, and overall status into column D. Then write a recommended action into column E: SKIP if disposable or no MX record, REVIEW if risky, SEND if valid.

Everything a reviewer needs to make the call — in one column.

Try It

Get the 7-day free trial of SheetXAI and open your prospect workbook, then ask it to run Mails.so validation for each email in column A and write the is_disposable, mx_found, and status results back. Also see how to validate a full campaign list before sending or review the full Mails.so integration overview.