Build a prospect list from results

Builds a reusable prospect list from a finished run. By default it keeps two kinds of address: ones whose mailbox was confirmed, and ones on a mail server that accepts every address. Pass keep=valid for confirmed-only, or keep=risky for catch-all only. The default mix is on purpose — many catch-all addresses still deliver — and the response reports the split so you can decide how to send.

Required scope: verification:write.

keep omitted is the same as campaign_ready (confirmed plus catch-all). keep=valid builds a separate confirmed-only list so it cannot collide with the default list.

confirmed_count is the mailboxes confirmed to exist. unconfirmable_count is the ones on a mail server that accepts every address — send to those gradually, with warmup running.

address_count is how many contacts ended up in the list after duplicates were collapsed, so it can differ slightly from the two counts added together.

The default list is named after your original run with "- Verified" on the end. Confirmed-only lists add "confirmed only". That is a label, not a promise about every address in it — read the two counts above for what is actually confirmed.

Calling it twice with the same keep returns the same list rather than creating a duplicate.

Costs nothing — the addresses were already checked when the run happened.

If the run produced nothing usable, the response is 200 with created: false rather than an error.