Authorea is a format-neutral editor.

Overleaf  and ShareLaTeX are built around LaTeX. For Authorea, LaTeX is just one of many potential formats. At the moment we offer LaTeX, Markdown, and HTML (rich text, like Word). Being format agnostic is a huge advantage: Authorea is for everybody, and it requires no knowledge of LaTeX or any other markup language. Authorea's rich text editor is a true WYSIWYG editor (What you see is what you get). It makes the experience of writing in Authorea identical to that in Google Docs or Microsoft Word. Users do not need to learn any complex markup. They use Authorea as they would use Google Docs with the additional scholarly features that make Authorea powerful: citation discovery and management, automatic bibliography, mathematical notation, tables, data, and one-click formatting and submission.