Hemingway is an app that helps writers catch errors. This goes well beyond spell check; it gives your writing a proper color-coded going-over and an overall readability score.
For example, Hemingway signals excessive adverbs as well as complicated language. It catches instances where you have written in passive voice or used splintered logic. Awesome!
You can use it online for free at HemingwayApp.com. Place the cursor at the beginning of the sample text already in the center of the screen. Write your text then select ‘Edit’. Here is what it caught in my first version of the previous paragraph of this post.
The app has been available as a web app for some time but is now also available for desktop (Mac or PC). This version will run you about $6.99 USD, as of the time of this writing.
My two cents is to realize that this wonderful app is not an exercise in exactness. You of course do not need to adhere to every suggestion it flags. This is a fantastic support tool but don’t turn off your brain or best judgment.