Verify email deliverability

The insight: "deliverable" is a tier, not a boolean — and every validator hides the riskiest tier behind its safest-looking field, in opposite directions. Verified live: ZeroBounce returns catch-all as status: valid (risk in sub_status); Enrichley returns it as valid: false (signal in result). Reading one top field either blesses bounces or discards live mailboxes — the verdict is always the field pair. The reverse trap: a live, monitored support@ comes back do_not_mail — validators grade for cold-list hygiene, not readership.

Declared inputs

Nothing here ships with a value. Each one is the installer's, not the author's: ask for it, never substitute a plausible default, and where an answer does not exist say which step becomes unavailable rather than guessing. Where a default IS defensible it is named below, and using it means saying so in the output.