Engagement rate is a composite measure of how actively subscribers interact with your emails — combining signals like opens, clicks, replies, and forwards rather than relying on any single metric.
In depth
Since Apple Mail Privacy Protection made opens unreliable, marketers increasingly define engagement around clicks and downstream actions. Mailbox providers also judge engagement (opens, clicks, deletions without reading) to decide inbox placement, so it doubles as a deliverability signal.
Example
Two lists both show a 30% open rate, but one has a 4% click rate and the other 0.8%. The first is genuinely engaged; the second is mostly passive opens. Segmenting out the unengaged and mailing them less often typically lifts overall deliverability.
Related terms
Learn which metrics to prioritise in our guide to email metrics.