What are those check marks next to my messages?

We are glad you asked. These green checkmarks are actually very important since they are indicators that acknowledge the delivery of a message. Here is what they mean:

 - message successfully delivered to the server. - message successfully delivered to the phone of your chat partner. Note: this does not indicate that the message was read, just that it was delivered. 

Also note that in a group chat you will only see one check mark indicating that the message was successfully delivered to the server.

If you only see a single green check mark next to your message, there is likely nothing wrong with WhatsApp or your phone. There may be several reasons why your message is delivered to the server, but not to your chat partner:

• Their phone might be turned off or their phone's battery might be dead.
• They could be sleeping, especially if they live in a different time zone.
• They may not be connected to the internet (for example, if they are in an elevator, roaming or have no data credits).
• They might have seen the notification on the screen, but did not launch the app to acknowledge message receipt (very common in case of iPhone recipients).
• They might have blocked you. For more information read this article.

Cheers,

WhatsApp Support Team