Email verification: how it works and what each status means

Draft — written from product facts + domain knowledge; UI labels to be verified before publishing.

Email verification checks whether an address can receive mail before you send to it. Every email unlocked from the lead database is verified automatically, and you can run verification on lists you upload yourself. Verified lists keep the bounce rate under 2–3%, which is the line between healthy and damaged sender reputation.

How verification works

Each address goes through a sequence of checks:

Syntax: is it a well-formed address.
Domain: does the domain exist and have MX records (a mail server).
Disposable / role check: is it a throwaway domain or a role address such as info@.
Mailbox check: OutreachFox connects to the mail server and asks whether the mailbox exists, without sending an email.
Catch-all detection: if the server says yes to a random made-up address, the domain accepts everything and the mailbox check is inconclusive.

Statuses


Status	Meaning	Send?
Valid	Mailbox exists and accepts mail.	Yes
Catch-all (accept-all)	Domain accepts any address, so the mailbox cannot be confirmed. Roughly 60–80% of these are real.	Yes, but isolate them in a separate campaign with bounce protection at 2%
Risky	Server responded ambiguously (greylisting, timeout), or the address is a role account.	Only after a second verification pass
Invalid	Mailbox does not exist, domain has no mail server, or syntax is wrong.	No
Unknown	Server could not be reached in time.	Re-verify later
Disposable	Temporary-email domain.	No

Steps: verify an uploaded list

Click Contacts and open the list.
Select the contacts (select-all for the whole list).
Choose Verify emails from the actions menu.
Confirm the credit cost if your plan charges for verification.
When the job completes, each contact shows a verification status column. Filter by status to remove Invalid and Disposable contacts and to separate Catch-all.

Tips

Verify every externally sourced list before uploading to a campaign, even if the vendor says it is verified. Vendor verification is often weeks old.
Re-verify lists older than 90 days; addresses decay at 2–3% per month.
Do not send to Risky or Unknown without a second pass; a second pass a day later usually resolves most of them.
Combine with Pause campaign when bounce rate reaches 3% on the campaign so any residual bad addresses are caught early.

Troubleshooting

Everything comes back Catch-all: your list is dominated by large companies, which commonly run catch-all domains. That is normal; send them at lower volume.
Verified list still bounced above 3%: check whether the bounces come from one sending mailbox (a mailbox problem) or are spread evenly (a data problem). Also check for a high share of catch-all addresses.
Verification is slow: mailbox checks are rate-limited by the receiving servers; 10,000 addresses can take an hour.

Unlock verified emails and how credits are charged
Managing bounced leads and cleaning your lists
Bounce protection: auto-pause a campaign at a bounce-rate threshold
Upload a CSV of contacts and assign it to a list

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More in Data & Enrichment

Lead database overview: search by ICP filters→Unlock verified emails and how credits are charged→Waterfall enrichment: append data fields to your contacts→AI enrichment: generate personalised first lines→Push found leads straight into a campaign→