Microsoft is emulating an approach taken by rivals Amazon and Apple in its effort to enhance its Cortana AI assistant platform.

The company has announced a preview version of Cortana Skills Kit, a software development kit aimed at getting third party developers to work on new functionality for the voice-controlled AI platform. The move takes a page from the Amazon playbook, with that company having significantly refined its Alexa voice assistant after launching its own Alexa Skills Kit in 2015; Apple has also gone this route, opening its Siri platform to third party development last year.

Opening Cortana to this kind of development is Microsoft’s latest effort to put Cortana front and center as a user interface. In a blog post announcing the Cortana Skills Kit, Microsoft asserted that there are already 145 million active Cortana users around the world, and said that by taking advantage of the new program, “developers can immediately reach the 60M users in the US and grow their international reach in the future.” Microsoft is also extending the reach of Cortana across platforms, with the AI assistant compatible with Windows 10, Android, and iOS, and coming soon to Xbox and other form factors including smart cars, the company says.

The Cortana Skills Kit already has some major partners on board to take advantage of it, including Expedia, Stubhub, Uber, and Dominos.