Create playlist API rejects documented `set_type=playlist` request only works when `set_type` is omitted

[Benjaminhu]

We found a mismatch between the documented and actual behavior of the SoundCloud playlist creation API.

Date observed: July 26, 2026

According to the public API schema, set_type accepts both:

• playlist
• album

However, in practice:

• set_type=album works
• set_type=playlist fails
• omitting set_type entirely works for normal playlists

Observed behavior:

• playlist creation succeeds when set_type is not sent
• playlist creation fails when set_type is explicitly sent as playlist
• album creation works when set_type=album

Expected behavior:

• set_type=playlist should work as documented

Actual behavior:

• the API only works for playlists when set_type is omitted

This suggests the documented enum is not fully supported by the live API.