Amazon announced on Monday that top playlists and thousands of stations are now available to stream for free on an ad-supported service.
The news did not go over well with Spotify investors.
Spotify shares dropped 5 percent on the news. Amazon shares were up nearly 0.5 percent.
The announcement was made in an Amazon blog post. Amazon Music customers who don't have a subscription to Amazon Music Unlimited or a Prime Membership can still get free music.
Up until now it was only available on Echo devices but has not been expanded to the most popular devices.
Spotify is the world's most popular music service with 140 million users on its free service, according to Reuters.