How to opt out of email validation

You can take your own email address out of every check we run. Send one email from that address to optout@email-validation.org. It is free and you do not need an account.

What email validation is

email-validation.org is an email validation service. Our customers, such as online shops, newsletters and software companies, check lists of email addresses before they send mail, to find addresses that do not exist and would bounce. A check asks the mail server of the address's domain whether the mailbox exists. No message is sent to you, so you would not normally notice that your address was checked. Read more in what is email verification.

Your address may be on such a list because you signed up somewhere, bought something, or someone typed it into a form. If you do not want it checked by our service, opt out.

How to opt out

1. Open the mailbox of the address you want to opt out.
2. Write a new email to optout@email-validation.org. The subject and the text can be anything, or empty.
3. Send it from that address.

That is all. Usually within a minute, you get one automated reply at the same address, saying that your address is now on our opt-out list. The reply says it is an automated answer; you do not need to answer it.

What changes

Within a few minutes of that reply, and from then on, whenever any of our customers checks your address, we answer only that the result is unknown. We no longer ask a mail server about your address, and we do not tell the customer that you opted out: the answer looks like a check we could not finish.

Opting out does not change results a customer received before you opted out.

What we keep

Our opt-out list does not hold your address. It holds only a one-way fingerprint of it (a SHA-256 hash): a fixed string of characters made from the address. The list does not contain the address itself, and we use the fingerprint only to recognise the same address when it is checked: we make the same fingerprint and look it up in the list.

Why it must come from your own address

We only act on a message that really comes from the address it was sent from. Most email providers prove this by signing every message they send with a digital signature called DKIM. Gmail, Outlook, iCloud, Yahoo and most other providers do this automatically; you do not need to set anything up.

• We look only at the From address of your message, never at a Reply-To address or at addresses in the text.
• A message without a valid signature for its From address is ignored, without any reply. This way nobody can opt out someone else's address, and we never answer a message that only pretends to come from an address.

No reply after an hour?

If no reply has arrived within an hour (check your spam folder too), your email provider may not sign the mail it sends. You can:

• ask your email provider whether it signs outgoing mail with DKIM, or
• write to privacy@email-validation.org from the address you want to opt out.

Every address opts out on its own

The opt-out list works one address at a time. If you have several addresses, send a message from each one. This includes aliases and forwarding addresses: an alias that delivers to your main mailbox is still a separate address, so send a message from the alias itself. Capital letters do not matter (Jane@example.com and jane@example.com are the same address).

Dots and + tags do matter. Gmail delivers jane.doe@gmail.com, janedoe@gmail.com and jane.doe+shop@gmail.com to the same mailbox, but for the opt-out list they are three different addresses, and each one opts out on its own: send a message from each spelling you gave out.

For our customers

An opted-out address answers unknown, like any check we cannot finish, and the check is free: like every unknown result, it uses no credit. We do not tell callers that an address has opted out, to protect its owner: the answer is the same as for any other check that could not finish.

See the unknown status for what an unknown result means and what to do with it.