Spotify requires linking back to their service per [their TOS] Section IV 3 g:
Metadata, Cover Art, and Audio Clip-Specific Restrictions. Metadata, cover art and Audio Preview Clips available via the Spotify Platform shall include a link back to the applicable artist, album, track, or playlist on the Spotify Service. You shall use the identifiers provided by Spotify via the Spotify Platform in order to comply with the restrictions in this paragraph. You shall clearly attribute that the Audio Preview Clips are being supplied and streamed by Spotify using the designated Spotify Marks on the player. You shall not offer metadata, cover art, and/or Audio Preview Clips as a standalone service or product.
This means Apollo should link back to artists or tracks on Spotify and make sure it's very clear that the preview tracks are coming from Spotify
Spotify requires linking back to their service per [their TOS] Section IV 3 g:
This means Apollo should link back to artists or tracks on Spotify and make sure it's very clear that the preview tracks are coming from Spotify