Flatpak is a cross-distribution framework to build and deliver sandboxed desktop apps. My open-source project, which focuses on the integration of web-based music streaming services with Linux desktop, has struggled with Linux fragmentation for years. Finally, I switched to Flatpak packages as the sole distribution method in March 2017 and I have never looked back.
What were the reasons to retire DEB & RPM packaging? Did Flatpak come up to my expectations? What are its benefits from the developer's point of view? How to develop directly inside the sandbox? Are there any rough edges?