Grammarly by Grammarly, Inc. is a well-known application that will help you check the spelling and grammar of your texts and it is available as both a web browser plug-in and MS Office add-in. Sadly, Grammarly for Mac cannot be used as a standalone app. However, there are several alternative programs that you can try. These tools can easily replace Grammarly for Mac. Some of these alternatives work offline and do not require registration.