Authorea allows you to insert snippets of LaTeX into your document. You can even go as far as writing your entire document in LaTeX. However, captions right now are limited to rich text. This is because LaTeX's caption environment is extremely sensitive to malformatted markup. For example, some export styles will complain (and fail compilation) if you insert newlines in the caption environment. To prevent this from happening, we only allow rich text in captions. However, you can still inject LaTeX in captions by clicking on the equation editor button x^2y in the toolbar. In the equation editor you can even edit the full LaTeX.
Updated on: 04 / 30 / 2020