Pattern inference is the method of working out a company's email address format, such as first.last or flast, from two or three addresses already seen on the domain, then generating the address for a new name by applying that format. Finders such as Hunter, Snov and FindyMail rely on it for people they have never seen. It works well on larger companies with a fixed format and fails on small firms with mixed formats, on hyphenated or non-Latin names, and on catch-all domains, where the server accepts any guess; 2.3% of business addresses in the 2026 corpus were catch-all, rising to 12.4% on .org domains.
Inference confidence is the share of known addresses on the domain that follow the chosen format. Three of three is high confidence; two of four is a coin toss, and finders usually show that as a lower score. Eight formats cover most companies; the company email finder guide lists them with examples.
The check after inference is a live verification. On a normal domain, a wrong guess is rejected at the server and the finder tries the next format. On a catch-all domain every format is accepted, so the finder reports success for a guess it never confirmed; only a verifier that labels catch-all separately exposes this.
A domain shows jane.doe@ and tom.smith@ in press releases. The format is first.last; the candidate for Priya Nair is priya.nair@. Verification returns valid. At a second company the two known addresses are jdoe@ and tom.smith@; no single format fits, confidence is low, and both candidates for the new name are generated and verified before either is used.
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Verify Leads - FreeAyoub built BounceZero's 5-stage validation pipeline, its dedicated BGP-announced IP infrastructure, and the Patroni HA PostgreSQL cluster behind every verification. Previously built high-volume email delivery infrastructure. Trained at 1337 Benguerir (École 42 network, 2019). Open-source: bgp_analyzer.