Gmail™ Notifier (Developer Edition) is a free-to-download, unofficial developer version of the popular email client. This extension does not require any kind of personal information to work, so it can be used by both private and public users.

You can use the Gmail Notifier to send and receive messages from Gmail, and it will automatically check for new emails, as well as mark them as read or unread.

Besides, you can use the app to do the following actions with the messages in your inbox:

Mark as read, report spam, archive, delete right from the popup view 

List all emails that match the current query on the popup view 

Create email threads for the messages

Create new labels, import or create new accounts, and assign those labels to your messages.