Read Receipts in Sendblue: iMessage vs SMS
Last updated: April 12, 2026
Last Updated: April 12, 2026
Customer-Facing Guide
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Read receipts work differently on iMessage and SMS. The most important rule: read receipts only apply to iMessage, not SMS.
The basic rule
| Message type | What to expect |
|---|---|
| iMessage | A message can move from delivered to read if the recipient opens it. |
| SMS | Read receipts are not available in the same way, so you should not expect a read status. |
How to tell the difference
Blue bubbles generally mean iMessage.
Green bubbles generally mean SMS.
If a message fell back to SMS, do not expect an iMessage read receipt.
Delivered vs Read
Delivered means the message was successfully delivered through the channel.
Read means the recipient opened the iMessage and the read state flowed back.
A message can stay delivered for a long time even if the message itself worked perfectly.
Common reasons customers think read receipts are broken
The message was actually sent as SMS, not iMessage.
The message was delivered but the recipient has not opened it yet.
The customer is mixing up delivered status with read status.
There is a dashboard/UI issue showing stale status even though the underlying send worked.
What to do before contacting support
Confirm whether the conversation is actually iMessage.
Check whether the message shows delivered first.
Make sure you are not expecting a read receipt on SMS.
If the issue looks inconsistent, gather a few example messages and timestamps.