Spotify has given its music purchase system a makeover, allowing users of the ad-funded streaming service to purchase tracks with one click within Spotify, without interrupting the music.

Spotify now has a closer integration with digital technology company 7digital, which provides the a-la-carte service. The 7digital API (application programming interface) allows partners to integrate with the company's technology and earn commission from tracks sold.

Users in the U.K., France, Spain and Sweden will have direct access to purchase from 7digital's 8 million strong MP3 catalogue via Spotify.

"This new integration makes the transaction process much more fluid and through these types of partnership we hope to fulfil our mission of making purchasing MP3s really simple," said 7digital CEO Ben Drury in a statement. "The 7digital API allows our partners to enhance their products or services by incorporating the option to download high quality MP3s, and the Spotify application is the perfect example of this. We believe this integration will substantially increase the amount of people listening to a song and then purchasing it for playing on their iPod or burning to CD."

Spotify is also available in an ad-free, high quality monthly subscription format, which allows users to connect via mobile devices such as the iPhone.