Open & Unique Open
Analytics. The record of each time a customer opens your Twilio Email email messages.
When turned on, Twilio Email inserts a small, transparent image into all emails. When a customer reads an email, their Mail User Agent (MUA) loads the tracking image. Twilio Email then registers the open event.
The opens percentage divides the total number of times your users opened your emails by the total number of Delivered messages.
The unique opens percentage divides the number of unique individuals that have opened your emails by the total number of Delivered messages.
Twilio stores unique open events for up to seven days.