Open Rate
The share of delivered emails that recipients open. A directional engagement signal that has become noisier as providers pre-fetch and mask opens.
Open rate is the percentage of delivered emails that get opened, traditionally measured by a tracking pixel loading. It reads the strength of the subject line and sender reputation, and a healthy open rate is a precondition for any reply — but it sits early in the funnel and does not by itself indicate interest.
Open rate has grown less reliable as privacy features like Apple Mail Privacy Protection pre-load images, inflating opens and masking who actually read the message. Experienced senders treat it as a directional signal for subject-line testing rather than a primary KPI, leaning instead on reply rate and meeting-booked rate, which measure outcomes that privacy changes cannot fake.
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