Another product that should be mentioned here is OX Documents [1] by Open-Xchange. They have a web-based Office suite with MS file types (docx, xlsx, etc.) that has a collaboration feature. However, the product is not 100% Open-Source (CCSA:NC) [2]. The source code is accessible, but you are not allowed to use it in a commercial product.
IANAL, but if you want to use the product yourself (even as a company) that should be just fine, but you are neither allowed to host the product for someone else (commercially) nor to created a product based on their frontend code.
IANAL, but if you want to use the product yourself (even as a company) that should be just fine, but you are neither allowed to host the product for someone else (commercially) nor to created a product based on their frontend code.
They also have a demo which you can try here:
https://gold.ox.io/admin-api/tryme/user/gold/assignment
[1] https://www.open-xchange.com/portfolio/ox-documents/
[2] https://en.wikipedia.org/wiki/Open-Xchange#Licensing