While Sonos is not proposing a solution to access your Sonos setup externally (like Plex, for example), unfortunately, we cannot directly retrieve your Sonos playlists.
A solution is to export your Sonos playlists in a file format like XML, CSV, etc... and make it compatible with Soundiiz format.
For iOS users, how to export Sonos playlists in Soundiiz format?
We recommend you use the Phonos Plus app, which can directly export a Sonos playlist in an XML format compatible with Soundiiz!
For non-iOS users, how can I export Sonos playlists in file format?
You can use the software MediaMonkey to export your Sonos playlists as EXTM3U, XPSF, or another format compatible with Soundiiz.
Once I have exported my playlists from Sonos, what should I do on Soundiiz?
Go to Soundiiz, and in the top right tab "Playlists" select "Import playlist". Then, follow the steps to match this playlist with music platforms supported by Soundiiz! A modal appears. Select "By File" and upload your file here.