How to Check Which Emails on a List Can Actually Be Verified
Before you verify a list, check how much of it can get a definite answer. The email verifiability checker sorts each domain on your list into four groups: providers that answer per mailbox (Gmail, Proton, iCloud), company domains, providers that come back risky (Yahoo, Outlook.com) and domains with no MX record. It checks no mailbox and sends no email. Only the unique domains leave your browser.
It tells you what to expect, so a large risky share is not a surprise.
Step 1: paste the addresses
Paste one address per line, or upload a CSV. The addresses are read in your browser and grouped by domain.
Step 2: check what can be verified
Consumer providers are matched against our published tests; every other domain gets one MX and SPF lookup. Up to 100 unique domains a run without an account, 500 after a Google sign-in.
Step 3: read the split
| Group | What it means for a mailbox check |
|---|---|
| Usually a definite answer | Gmail, Proton, iCloud and similar answer per mailbox |
| Depends on the company | Company domain; catch-all is only known once it is probed |
| Expect risky | Yahoo and AOL accept every address; Outlook.com is not probed |
| Likely to bounce | The domain has no MX record |
Counts are by addresses, not domains. You can download the CSV, or send the addresses that can get an answer straight to a mailbox check. The evidence is in how 51 mailbox providers answer verification checks.
Reading it honestly
A list heavy in Yahoo, AOL and Hotmail will show a big risky share, and that is the honest outcome, not a weak verifier. For those rows, see verifying Yahoo addresses and verifying Outlook and Hotmail addresses. For company domains, see what is a catch-all domain.
What this check cannot do
- It checks no mailbox, so it cannot say which addresses are real.
- Whether a company domain is catch-all is only known once it is probed.
- Provider behaviour is from our published tests and can change.
- Providers we have not tested are shown as not known yet rather than guessed.
Verify the list
Upload it on the verify page: the first 100 email checks are free with a Google sign-in, no card. Each address comes back valid, risky or invalid with a reason such as "Mailbox exists", "Mailbox not found", "Accepts all addresses" or "Disposable address". See bulk email verification and pricing.
Check your list now
Paste it into the email verifiability checker.
Common questions
Can you verify Yahoo email addresses?
Not one by one. Yahoo's servers accept any recipient during the SMTP conversation, including made-up ones, so a verifier cannot tell a real mailbox from a fake. SimpleVerifier returns Yahoo and AOL addresses as risky with the reason 'Accepts all addresses'.
Why are Outlook.com and Hotmail addresses risky?
Microsoft is currently refusing mailbox checks from our server's network, so we do not send them a probe. Those addresses come back risky with the reason 'Provider hides mailbox status'. Company domains on Microsoft 365 are probed like any other company domain.
Does this tool check whether the emails exist?
No. It checks no mailbox and sends no email. It tells you what a mailbox check can confirm on each domain, from our published provider tests and the domain's MX record.
Which providers can be verified?
In our tests Gmail, Proton, Yandex, Zoho and iCloud answer mailbox checks one address at a time. Most company domains do too, unless they are catch-all.
Are my addresses uploaded?
No. The list is read in your browser and only the unique domains are sent to our server.
Check your list before you send
Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.