How we check email addresses

Every address that joins your list is checked, whether it comes from a form, your newsletter page, an invite, an import or the API. The checks are free on every plan, with no credits or meters.

Checking an address is separate from permission. A valid address still needs its owner to subscribe before you can email them.

The checks, in order

1. Format. Spaces are trimmed and the address is lowercased. An address that isn't shaped like an email is refused.
2. Domain. If the domain doesn't exist or can't receive email, the address is marked Invalid straight away.
3. Already on your list. We reuse the subscriber you already have instead of adding them twice. Someone already subscribed sees "You're already subscribed".
4. Your blocklist. Your own blocked addresses, domains, countries and settings (below).
5. Typos. An address like name@gmial.com is refused with "Did you mean name@gmail.com?" until the person fixes it. We never change an address for them.
6. Throwaway addresses. Known disposable and temporary email services are caught from a list we keep up to date.
7. Mailbox check. Our checking service confirms the mailbox can receive email. Results are reused for 30 days, or 90 days for an Invalid address, so the same address isn't checked over and over.

Imports flag typos instead of refusing them, so you can review them.

What each status means

Status	Meaning	Can you send to it?
Verified	The mailbox exists and accepts email	Yes
Risky	The domain accepts any address, so we can't confirm this one	Yes
Unverified	We couldn't check it yet, so we'll try again later	Yes
Invalid	The address can't receive email	No

If the checking service doesn't answer, the signup still goes through as Unverified. A slow check never breaks your forms.

A second check at send time

Just before each email goes out, Amazon SES checks every recipient again. If it finds an address that can't receive email, we mark that subscriber Invalid and skip them. This never counts as a bounce against you.

Your blocklist

Find these in Settings, Blocklist. They apply to signups, invites, imports and the API.

Setting	What it does	Starts
Block disposable emails	Refuses known throwaway services	On
Block temporary emails	Refuses burner addresses that expire	On
Block mistyped domains	Refuses name@gmial.com and asks for a fix	On
Block cross-newsletter signups	Refuses an address already subscribed to another of your newsletters	Off
Block alias emails	Refuses addresses with a + in them	Off
Block free email providers	Refuses Gmail, Yahoo, Outlook and similar	Off
Block role addresses	Refuses info@, sales@, support@ and similar	Off
Block catch-all emails	Refuses Risky addresses instead of accepting them	Off

You can also block single addresses, whole domains and countries. A country is worked out from where the signup came from.

Blocking someone who's already a subscriber stops your emails reaching them. Their history stays as it is.

What subscribers see

When an address is refused, the person sees a short, plain reason, such as "Disposable email addresses aren't allowed." They never see technical codes.

Who you can send to

An email only goes to a subscriber when all of these are true:

• They subscribed to the newsletter you're sending from, and haven't left.
• Their address isn't Invalid.
• They haven't been blocked, by you or by us.
• They're in the email's audience and not in its exclusions.
• Your account can send today (see Account limits and Sending reputation).
• Your sender address and sending domain are still verified.

We check this when we show you the recipient count, when the email starts sending, and again just before each email leaves.