Hemingway, developed by Adam and Ben Long, is a small website where you can have your text analyzed against a variety of clarity-focused metrics. From the home page:
Hemingway highlights long, complex sentences and common errors; if you see a yellow highlight, shorten the sentence or split it. If you see a red highlight, your sentence is so dense and complicated that your readers will get lost trying to follow its meandering, splitting logic — try editing this sentence to remove the red.
Although the syntax parser could use some tweaking (and Markdown support for that matter), I personally liked Hemingway’s presentation of “sentence syntax” over that of Information Architect’s Writer Pro.
Hemingway, as the name implies, tries to enforce a very bold and clear writing style, emblematic of Ernest Hemingway. I personally enjoy this style of writing; however, as new syntax- and grammar-focused tools start to appear, it is important to remember that there are no true hard rules of grammar. You can break any of these “rules” you want, just be sure to do so with purpose.
—Wednesday, 12 February 2014