Since Apple Music launched at the end of June, over 10 million customers have signed up for the service. Sources from major labels are said to be surprised and impressed by the amount of subscribers Apple have enticed so far.

Although Apple hasn’t revealed any official numbers, Hits Daily Double‘s “inside sources” say that Apple Music has had a very successful first month, already pulling in more than 10 million subscribers. This is due in large part to the fact that Apple is not charging customers during the first three months of the service, attracting many to give it a go while it’s still free. In fact, 9to5Mac are surprised the numbers aren’t even higher considering it’s available for free to anyone running iOS 8.4.

To give the figures some context, rival streaming service Spotify currently has around 75 million total users, but only 20 million of those are paid subscribers. If Apple can retain and build on a strong start it could prove to be a serious contender in the streaming service game. How many of the 10 million are only going to stick around beyond the trial is anyone’s guess.

Though the early numbers are relatively strong, we’ll see a much more telling representation of Apple Music’s success when the free trial ends in late September.

Read more: can Apple Music become a power player in the music streaming game?