Confusables catches the most commonly confused English words — its/it's, your/you're, then/than, who's/whose, lets/let's, and there/their/they're — and corrects only those words, leaving the rest of the text untouched. Also could of → could have, along with should of and would of, lose/loose and affect/effect.

Or try one — a mistake from each rule:

• Its been a long day
• Your the best
• This went better then that
• Who's keys are these?
• Lets go now
• Their going to love it
• I could of helped
• Don't loose hope
• The affect was clear
• Its been a long day at its-been.com