Deliverability
Deliverability
Deliverability is whether your email reaches the inbox rather than the spam folder or nowhere at all. It is decided by sending reputation, authentication and list quality — not by your copy.
It is worth separating from delivery. Delivery means the receiving server accepted the message; deliverability means a human saw it. A campaign can be delivered at 99% and read by almost nobody, because everything landed in a folder nobody opens.
From the sender's side a deliverability problem and a copy problem look identical: silence. That is why checking the mechanical layer first is not pedantry — rewriting a subject line for three weeks does nothing if the domain has no authentication records.
Goes deeper: Why Your Cold Emails Land in Spam