Spotify just gained another rival in Pandora as they’ve launched a free on-demand streaming tier supported by ads.

Free streaming was Spotify’s bread and butter but more and more services are getting in on the game. Pandora just surprise launched a free tier that allows users to sign up and listen to their giant library of music at no cost.

The tier will be supported by offering you to watch a 15-second advertisement before listening to a track. If you watch the ad then you unlock a “Pandora Premium listening session” in which you can listen to uninterrupted music on Pandora’s app.

Pandora say in their announcement: “We’re serving up the most personalized listening experience by letting you lean in to listen to music on-demand, or lean back and let us take over with recommendations unique just to you.”

Pandora started in radio streaming and grew a massive audience thanks to its intuitive discovery and recommendations in stations. At the start of this year Pandora began their exploration into on-demand streaming with Pandora Premium, which allowed you to pay for a subscription and listen to unlimited music.

Pandora Premium Access is available on their iOS and Android apps. Unfortunately free listening isn’t coming to their web player just yet.