There are a variety of free and paid grammar checkers on the market. Some are better for fiction than others. None of them are perfect.
KJ Matthews discovered that when her grammar checker suggested that seven teenagers needed to go feeling each other rather than fishing with each other. We don’t want to know about seven teens feeling themselves!
Many writers assume that the grammar checkers know what a sentence should read better than the author, but if you do that, you risk losing your author voice. That is what makes your work sound like yours. Author voice allows the readers to hear each character distinctly in their heads. But grammar checkers have their place.
We use grammar checkers as one of the stages of line editing (each book we edit goes through at least six line edits depending on how many weasel words there are). It’s usually the second last stage of line editing because prior to that, we are perfecting each sentence or “line” to make it the best it can be.
Grammar checkers allow the author to focus on the technical aspect of grammar—you know that stuff you forgot from school!