Chord decoding services are used to help determine the chords used in a song. This can be helpful when trying to learn a new song, or when trying to figure out how to play a particular section of a song. Chord decoding services can be used to decode chords from a recording, or from a live performance.
There are many websites that offer chord decoding services. This is a service where you can input a chord progression and the website will output the individual notes in the chords. This can be helpful for understanding how a chord progression is constructed, or for learning new chords.
There are many decode chords services available online, but not all of them are created equal. Some are better than others, and some are more expensive than others. Do your research to find the best decode chords service for your needs.