What a read receipt records
A messaging app can track more than whether a message reached a phone. When the recipient’s app opens the conversation and displays the message, it can mark that message as read and send the status back to the service. The sender’s app then shows a read receipt, often after syncing that update across devices.
That is a different event from delivery. A delivery confirmation means the message arrived at a device or account; it does not establish that the conversation was opened. A read receipt records that the app displayed the message in the chat.
Displayed is not the same as understood
The receipt is evidence of an interface event, not a window into someone’s attention. A person might open a chat while distracted, glance at the screen, or have the message appear without taking it in. Conversely, a notification preview may let someone see some or all of a message without opening the conversation, so the app may not mark it as read.
The exact rules depend on the service. Apps may let users turn receipts off, handle group conversations differently, or delay updates while a device is offline. The useful distinction is what the status can establish: delivery says the message arrived; a read receipt says the app registered it as displayed in the conversation—not that the recipient consciously read or understood it.
