Spytify is a general-purpose application audio recorder, in the same category as Audio Hijack, Loopback or OBS. This is not legal advice.
A recorder, not a downloader
Spytify downloads nothing, emulates no streaming protocol and circumvents no DRM. It records audio the operating system already plays on your speakers, in real time.
Stream downloaders pull files through a service’s own protocol, and those are what services go after with legal action. A recorder only reaches your account: that difference is why Spytify is still around.
Your account
You bring your own account for the application you record. Recording may break that service’s terms, and the service can suspend or close accounts that do. It is rare, and it has never happened to the maintainer, but use a separate free account, not one you would mind losing.
Where you live
Private-copy rules differ from country to country. Spytify does not promise that recording is legal where you live.
For personal use of content you are entitled to listen to. You are responsible for the terms of the services you record.