Apiary.io help you to design, prototype, document and test APIs collaboratively as a team. If you ever want to share the API documentation with non-apiary.io users as a PDF or Styled HTML, then you can copy the markdown format text from apiary editor, paste it on http://dillinger.io and use it Export As feature.
Screenshot from Apiary.io in Documentation mode:
Screenshot from Apiary.io in Editor mode:
Screenshot from http://dillinger.io/:
