open source no-signup online text editor

I found it hard to find an easy way to share a doc with a friend collaboration.

I try using vercel, MongoDB, and jquery. The simplest way to build a free product.

No Signup is required, use a random id as a secret and every doc has a share code change every day.

Try it here. https://doc.op52.com
Source code here: https://github.com/tans/online-editor.git

I want to know how to keep user content secret because I can read everybody's writing directly in MongoDB.

Thank's to vercel and mongo, I could build software so easily, with no server fee, and no maintenance work.