It violates Spotify’s ToS but is generally legal to use for personal backup in countries with fair use laws. Selling converted music is illegal.
This article explains how the licensing system works, the risks of using unofficial codes, and legal alternatives. What is UkeySoft Spotify Music Converter? ukeysoft spotify music converter registration code
The automated system will instantly send a unique registration code (serial key) to your provided email address. Activate the Software: Launch UkeySoft Spotify Music Converter on your computer. It violates Spotify’s ToS but is generally legal