Gmail REST API Addon
Easy to integrate Gmail Service for sending transactional emails, using official Google API PHP Client Library into the GD Mail Queue Pro plugin for sending all regular and queue emails.
Start with Gmail REST API Addon here
Mail Engine: Gmail REST API
Most Helpful Content for Gmail REST API Addon
Can I translate addon to my language?
Yes. POT file is provided as a base for translation in the root folder for each plugin. Translation files should go into languages directory, and WordPress must be set to your language to load the file. The file name for translated and compiled MO file must be the same as POT file with the addition of language code: {addon-name}-{language-code}.mo.
You can check out this for translating plugins using POEdit program:
wp.dev4press.com/tutorials/translating-plugins-or-themes-using-poedit
Can I use this addon with GD Mail Queue Lite/Free version?
No.
The addons are made for the GD Mail Queue Pro, and there are no plans to have addons supported in Lite/Free version.