ISEMAIL only checks if an address looks right. Here is how to confirm a mailbox actually exists, from a formula to a real Apps Script to a no-code path.
Clean my Google Sheets list, free Bulk verifier 100 free credits, no card. Pay only for Passed & Failed. Credits never expire.Google Sheets' built-in ISEMAIL function (and any REGEXMATCH pattern) only confirms an address is formatted correctly. It cannot tell you whether the mailbox actually exists, so a sheet that passes ISEMAIL can still be full of bounces. Real verification needs a live check against the mail server, which you add with a short Apps Script or a no-code add-on.
The specific ways an unverified Google Sheets list costs you money and deliverability.
TRUE from ISEMAIL means the syntax is valid, not that the address is real. Dead mailboxes pass it every time.
Eyeballing a column or writing ever-longer regex will never detect catch-all, disposable, role or non-existent addresses.
If you send or import straight from an unverified sheet, the bounces and reputation damage follow.
The accurate, current steps, from export to a clean, safe-to-send list.
Use =ISEMAIL(A2) to flag badly formatted addresses. It is a useful first pass, but remember it confirms format only, never that the mailbox exists.
Open Extensions, Apps Script, and use UrlFetchApp.fetch() to call the Email Verifier API for each address, then parse the JSON status back into a column. Add an onOpen() menu so anyone can run it without touching code.
Apps Script runs cap at about 6 minutes and UrlFetchApp has a daily quota, so batch large lists across runs and add a short Utilities.sleep() between calls.
Prefer no code? Export the sheet to CSV and run it through the bulk verifier, then paste the clean results back. Same 16-point accuracy, zero scripting.
What the native option does, and where real verification fills the gap.
| Capability | Google Sheets (native) | Email Verifier API |
|---|---|---|
| Checks if mailbox exists | No (ISEMAIL = format only) | Yes, live SMTP check |
| Catch-all / disposable / role | No | Yes, flagged clearly |
| Works on large lists | Manual / limited | Yes, batch or bulk upload |
| No-code option | No | Yes, CSV upload |
| Credits expire | n/a | Never |
Cleaning your Google Sheets list, answered.
No. ISEMAIL checks that an address follows a valid format. It cannot confirm the mailbox is real or deliverable. For that you need a live verification call, which you add with Apps Script or by exporting the sheet to a bulk verifier.
In Extensions, Apps Script, use UrlFetchApp.fetch() to send each address to the Email Verifier API, parse the JSON response, and write the status back to a column. An onOpen() custom menu lets non-technical users run it in one click.
Script executions are capped at roughly six minutes and UrlFetchApp has a daily quota, so for large lists process in batches and add a small delay between calls to stay within rate limits.
Yes. Download the sheet as CSV, run it through the bulk verifier, and paste the cleaned results back. You get the full 16-point check with no scripting at all.
Pay-as-you-go, one credit per address, billed only for Passed and Failed results, credits never expire, and 100 free credits to start.
Start with 100 free credits, no credit card. See exactly how many of your Google Sheets contacts are about to bounce.
Verify my list free