How to judge whether an address will bounce
There is no single true/false verified column. The deliverability signals live inside the All emails JSON — what each one means, and what none of them can promise.
There is no verified column in the export, and that is
deliberate. A single boolean flattens several different facts into one, and the one it flattens
them into is the one people over-trust. The signals are published individually instead, inside
the All emails array that
the enrichment columns describes.
The signals, per address
| Field | Means | How to read it |
|---|---|---|
has_mx | The domain has a valid MX record — something is configured to receive mail at all | false is the strongest negative signal in the file. Do not send. |
mx_provider | Who runs the mail: google, microsoft, cisco, other | Useful for pacing a send. Large providers judge you on bounce rate hardest. |
is_webmail | The address is on a consumer mail provider rather than the business’s own domain | Common for sole traders. Deliverable, but a weaker signal that you have reached the business. |
is_disposable | The domain is a known throwaway-address service | true means skip it. |
category | Which kind of mailbox it is — individual, info-contact, sales and so on | Not a deliverability signal, but it is what decides whether anyone reads it. |
sources | The URLs the address was published on | Evidence. An address found on the business’s own contact page is worth more than one found once in a footer. |
What none of this promises
- It does not mean a human reads it.
info@at a business that abandoned the address in 2019 has a perfect MX record. - It does not mean the mailbox is live today. The checks happened when we last read the site. Mailboxes are closed all the time.
- It does not mean the address belongs to a decision-maker. It is the address the business published, nothing more.
A strong signal, not a guarantee
Treat has_mx: true on a non-disposable, non-webmail domain as "worth sending
to", and everything else as "expect a higher bounce rate". Nobody can honestly promise more
than that about an address they did not create. Anyone who does is grading their own
homework.
Catch-all domains
Some domains accept mail to every address, real or not. On such a domain no external check can distinguish a real mailbox from an invented one. This matters far less here than it would for a vendor that guesses addresses, because we only publish addresses the business itself published — see why a listing has no email. We are never asking you to trust a check on an address nobody wrote down.
How to use it in practice
- Warming a new sending domain? Send only where
has_mxis true andis_disposableis false, and prefer the role column that matches your message. Bounce rate is what mailbox providers judge you on. - Established sending reputation? Include the weaker rows too, but in a separate campaign so one list's bounce rate cannot poison the other's stats.
- Always run your own verification pass immediately before a send if the export is more than a few weeks old. No stored signal survives contact with a mailbox that was closed last Tuesday.
Filtering on it
The Has an e-mail on the website filter tests presence, not deliverability. Export with it on and then sort on the fields above. Filtering on presence rather than on a quality judgement is deliberate: it keeps the credit cost predictable and leaves the judgement with you, where it belongs.
Why we publish signals rather than an accuracy percentage
A single headline accuracy number across 4,000 categories and every indexed market would be
meaningless, and every vendor grades their own. Per-address provenance in
sources, plus the Link column straight to the map listing, lets you
grade us on your own market instead. That is what the free trial
is for, and it takes no credit card.
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