I used to only have Chrome to use an extension which does the same thing. Super happy to finally leave that behind because this exists.

It works on android which is awesome! The semitones are inaccurate. I'm not 100% what the error is but it seems 12 semitones in the app = 5 semitones IRL.

Es justo lo que necesitaba. Hasta ahora no había ninguna alternativa funcional a la extensión "Trasposer" de Chrome para Firefox. Me gustaría que también funcionara con Spotify. Gracias :)