What is a risky email?
Also called: unknown, unverifiable, accept-all result
Risky is the verification status for an address on a working domain whose mailbox could not be confirmed. It covers catch-all domains that accept every address, servers that refused to answer, and greylisting. It is not a soft form of invalid — it means the check was inconclusive and the truth is unknown.
The risky category is the honest part of a verifier and the first thing removed by a vendor optimising for a marketing statistic. Collapsing risky into valid produces a higher apparent accuracy rate and hands the bounces to the customer; collapsing it into invalid discards deliverable addresses.
Our rule is that anything the probe could not confirm is returned as risky, never as valid. The test for any vendor is to verify an address you invented at a real domain — a valid result means no mailbox check happened.
How to use them: send to risky addresses in a separate, smaller batch, on a subdomain if you have one, and watch the bounce rate before committing the rest.
Last reviewed 2026-09-11