As a fellow API practitioner and API enthusiast, I love listening to T-Pain as I'm shredding it on the front-end.
T-Pain absolutely was the one who popularized it through. To the point that among the general public "Auto Tune" is associated more with "electronic voice effects" than it is with "pitch correction."
He popularized using Auto Tune for electronic voice effects.
R&B Artist. Recently had an album of covers: https://www.youtube.com/watch?v=i4nMjyT4epA