That essentially means, if you have a Spotify Connect-enabled speaker you will be able to listen to ad-supported, free streaming of music.
Until now, Spotify Connect streaming on separate devices has only worked with a Spotify Premium account.
Your speaker might not be compatible with the free service quite yet as its manufacturer will need to update the device first. However, this is a major step for integration and will open up music streaming support to a much wider audience.
Spotify has more than 100 million users of the free version of its streaming service.
"The release of our new eSDK will change the game for Spotify’s Free users who want to enjoy music on their connected speakers. We look forward to supporting our partners over the coming months as they update existing speakers and bring new products to market," said Spotify's senior product director, Mikael Ericsson.
Manufacturers can download the Commercial Partners SDK from the Spotify for Developers website here.
You can also find out more about the Spotify Free service and the Spotify Premium subscription benefits and prices on the main Spotify site.