I use Grammarly for proofreading because my mind runs faster than my fingers.
Besides the above tongue and cheek, Grammarly is a fabulous tool I found by accident. The folks at Grammarly reached out to me for a test drive. At first, I thought they were sent by some old english teacher who had been following my every sentence.
I used the online tool in a couple of situations and it performed well. It's fabulous for the daily writer or the professional who needs to make the best impression possible. My wife asked me whether I could try the free tool in WordPress or Word. That's an option, I want something as robust as Grammarly. You can sign up for a free trial at their site to see if it's a fit you.
By the way, it won't cramp your ability to get your message out. We all know how important a message is.