A verified email is one a provider has checked against the receiving mail server, confirming the domain accepts mail and the mailbox exists. It is different from a pattern-guessed address, which is assembled from a name and a domain and has never been tested against anything.
Why it matters
The two are sold under the same word and cost you very differently.
A pattern guess is right often enough to look useful and wrong often enough to damage you. Mailbox providers track how much undeliverable mail a sending domain produces, and a run of bounces lowers deliverability for every message your team sends afterwards, including to addresses that were fine. The wasted credit is the small half of that cost.
Example
Your data vendor returns jane.doe@acme.com for Jane Doe at Acme. Two ways that could have happened:
- The provider queried Acme's mail server, which confirmed the mailbox exists. That is verified.
- The provider observed that Acme uses
first.last@and assembled the rest. That is a pattern guess, and it fails silently for everyone at Acme who predates the convention, married, or goes by a shortened name.
Both come back as a string in the same field. Only one of them has been tested.
Common mistake
Reading a published accuracy percentage as a promise about your list. Accuracy figures are averages across a whole database, and they hide the segments where it falls apart: smaller companies, non-US geographies, senior titles, and catch-all domains, where the server accepts everything and therefore confirms nothing.
Ask your vendor one question instead of comparing percentages. Did a mail server answer, or did a pattern match?
How this relates to Signl
enrich_lead returns a contact record with an explicit email_verified boolean, so the answer to that question is a field rather than an inference. Credits are charged only when a verified result comes back. A lookup that finds nothing, or finds only an unverifiable address, costs you nothing, because we pay the provider for that attempt and you should not pay twice.