Email verification, and what it can prove

Email verification checks that an address can receive mail before you send to it. It protects your sending reputation, because a message to an address that does not exist bounces, and too many bounces teach mailbox providers to distrust you.

What gets checked

Syntax: the address is correctly formed.
Domain: the domain exists and has mail servers listed in its records.
Mailbox: the mail server confirms the specific mailbox exists, where it will say so.

What it cannot prove

Some mail servers accept every address and decide later, so a check cannot tell whether a particular mailbox is real. These are called catch-all domains. An address on one is unproven rather than bad, and is better treated with caution. Verification also cannot tell you whether a person will read or answer the message.

Why bounces matter

A hard bounce means the address does not exist. A handful is normal, but a high rate signals poor list quality. Mailbox providers use that signal when they decide whether your future mail reaches the inbox, and a new domain has little reputation to spare.

Guessed addresses

Guessing patterns such as [email protected] and sending is risky: some guesses fail, and some reach the wrong person. A guessed address should be checked like any other and labelled as inferred until it is proven.

A sensible policy

Send only to addresses that have been proven.
Keep unproven and catch-all addresses out of the first send, or send to a small number at a time.
Re-check old lists before reuse, because addresses change.
Watch the bounce rate after every send and stop if it rises.

How Accumen handles it

Accumen checks every address against the company's mail server before it is offered. An address is shown as verified only when it has been proven. Inferred and catch-all addresses are labelled as such, and only verified addresses are exported as verified. The first 25 verified contacts are free, with no card.

Frequently asked questions

What is email verification?

It is checking that an email address can receive mail, by testing its format, its domain and, where the server allows, the specific mailbox, before you send.

What is a catch-all email domain?

It is a domain whose mail server accepts every address. A check cannot tell whether a given mailbox exists there, so such addresses are unproven.

Why do bounces hurt deliverability?

Mailbox providers treat a high bounce rate as a sign of poor list quality and may filter your future mail to spam or reject it.

Does verification make sure the email is delivered?

No. It reduces bounces, but it cannot ensure inbox placement or that the person will read the message.