Shazam is my favorite app of all time. They target the pain point of hearing a song that you like and spending eternity trying to search things like “la lalala la” into Google. Shazam works by pressing a button on the app and putting the phone near the music source. Within 5-10 seconds the app tells you the name and artist of the song, and gives you download options. It saves all off the songs you’ve shazamed, so you can access them later on. It also provides a list of what songs are popular right now, as well as which songs will be popular in the future. They do this through looking at the number of Shazams for each song. Right when you open the app, it gives you a big button to press to begin the song identifying process. I like how it gives you the button right away; sometimes a song is about to end and you need to know what it is really quickly.
The app works by fingerprinting a large catalogue of music. The user uploads a 10 second fingerprint of a song through recording audio on their phone, and Shazam searches through their database to find a match.