Key takeaways
- Verification tests whether an address can receive mail, not whether it is the right person.
- Catch-all domains accept every address, so verifiers cannot confirm them.
- A confidence score estimates likelihood; verification tests the mailbox.
- Verify close to the send date, because addresses go stale.
What does email verification check
Email verification checks an address in layers, from its spelling to the receiving server's answer. Each layer removes a different kind of bad address.
- Syntax: the address is correctly formed.
- Domain: the domain exists and has mail servers set up to receive.
- Mailbox: the server is asked whether that mailbox exists, without delivering a message.
- Risk flags: disposable domains and shared role addresses such as info or sales.
Why do catch-all domains defeat verification
Catch-all domains defeat verification because their servers accept mail for any address at the domain, real or not. When the verifier asks whether a mailbox exists, the answer is always yes, so the check proves nothing.
Verifiers usually mark these addresses as unknown or risky. Some of them work and some bounce later or vanish silently, so treat them with care and send to them in small numbers.
Is email verification the same as email validation
Usually the two terms mean the same thing. Where people separate them, validation means checking the format of an address and verification means checking the mailbox exists.
Neither checks that the address belongs to the person you think it does. A valid, working address can still be the wrong person, or a colleague's shared inbox.
How does email verification compare with a confidence score
Email verification tests a mailbox, while a confidence score estimates how likely an address is to be correct from patterns and evidence. A high score with no verification is a good guess; a verified address with no score is a working mailbox that may or may not be the right person.
Pebbles Ai gives each work email it finds a confidence score and a catch-all flag, which help you judge each address. If you plan a larger send, run the addresses through a verification tool as well.
Where Pebbles Ai fits
Common questions
Does email verification send an email?
No. A verifier talks to the receiving server and stops before any message is delivered, so the person never sees anything.
Does a verified email always reach the inbox?
No. Verification only says the mailbox exists. Spam filters, sender reputation and content still decide whether a message lands in the inbox.
How often should you verify an email list?
Shortly before each send to a list you have not used recently. Addresses decay as people move on, so an old verification result says little.
About this page. Written by the Pebbles Ai team for people who run sales, marketing and growth. Last updated .
