If you're looking for an app to help you figure out chords and beats in a song, ChordAI is the most powerful option. It uses deep learning technology to identify chords and beats in a variety of sources, including YouTube, SoundCloud and audio files, and has an option to use your phone's microphone for real-time input. It's got a chord dictionary with diagrams for guitar, piano and ukulele, and other features like instrument separation, audio to MIDI conversion and lyrics recognition.
Another good option is Moises, which has a variety of AI-based audio editing tools, including real-time chord detection. The app also can generate a smart metronome, change the pitch of an audio file and detect the key of a song. That makes it good for musicians who want to practice songs in different tempos and keys. Moises can separate vocals, drums, guitar and bass, too, giving you a better idea of the song's rhythm and harmonies and helping you practice and be more creative.
For a more general-purpose site, Fadr offers a collection of AI-based music tools, including a key/tempo/chords detector, vocal remover and remix maker. You can upload songs and extract different audio stems, and the site will identify the tempo, key and chord progression. Fadr offers both free and premium accounts, so you can use it at different levels of sophistication.
The apps are powerful, with a lot of features that can help you with everything from figuring out chords and beats to editing and manipulating audio samples. If you want something easy to use and all-purpose, ChordAI is a great choice, but Moises and Fadr are good for musicians who want to be more creative.