What is latency in email?

Latency in email refers to the time it takes for a message to travel from the sender's system to the recipient's inbox. This includes every hop along the route, DNS lookups, SMTP handshakes, spam and virus scans, and any queuing delays inside MTAs (Mail Transfer Agents).

Behind the scenes, an email can cross multiple servers and networks before final delivery. Typical latency is measured in seconds, but spikes into minutes or hours often indicate throttling, greylisting, or infrastructure congestion.

Consistently high latency doesn't always mean rejection, it means your ship is sailing, but against the wind. For transactional emails, even a delay of a few minutes can erode trust and conversions, so monitoring latency is as critical as tracking deliverability.