Hello dear team,
Its long time ago that support of Overleaf has worked. I wrote already a letter to Overleaf and to you (LanguageTool) — and both says: “please contact Overleaf→LanguageTool; LanguageTool→Overleaf”.
Maybe you can contact them by self and try to integrate your service? I think it’s a win-win situation!
Thank you for advice!