Sending
CraftNudge is the sending engine, not a mail server. It drives the inboxes you already own — spacing, rotating and throttling sends the way a careful person would, and stopping the moment a conversation starts.
Your own inboxes, over SMTP. Google Workspace via app password is the common case; any SMTP + IMAP provider works.
A campaign draws from a pool of inboxes you attach. Each send picks the least-used inbox that is under its cap and past its gap.
A daily limit per inbox, a gradual ramp-up for new mailboxes, and a minimum gap between sends with random jitter so nothing looks machine-timed.
A timezone, the days of the week, and the hours you choose. Nothing sends at 3am unless you ask it to.
A follow-up with an empty subject inherits the previous one and lands in the same thread — Re:, with the right In-Reply-To and References headers.
The instant a lead replies, their sequence stops. No awkward follow-up after someone already answered.
A 4xx deferral is caught, the send is retried later rather than burned, and it shows up as an early warning that the inbox is being pushed too hard.
A disconnected or failing inbox drops out of the rotation and is flagged on the Inboxes screen, with the reason Google gave.