I made this project in my free time a few years ago, to organize my own documents, and then decided to use my newly created company (2 guys) to make a real product out of it.

There is a self-hostable version on Github also (Docker image working out of the box).

The server part is made in Java with an embedded H2 database and a Lucene index, and the frontend is mostly AngularJS.

Feel free to try out the demo and give me some feedbacks!