Yes. We are making the entire source code (frontend and backend) open source under the AGPL v3 license. This liscense allows others to contribute to holi and use (parts of) the code. Everyone who modifies our code or packages it with other functionalities needs to open source their code as well. Details about the license can be found here: https://www.tldrlegal.com/license/gnu-affero-general-public-license-v3-agpl-3-0