LanguageTool is an Open Source proofreading software for English, French, German, Polish, and more than 20 other languages.
It finds many errors that a simple spell checker cannot detect and several grammar problems.
Make your browser window wider to get a text field where you can try out LanguageTool directly or use this simple form.
Please see our checklist if you experience problems. Download old releases or daily builds. Start with Java WebStart.
LanguageTool is freely available under the LGPL 2.1 or later.
The source is available on github.