The phrase "across a number of platforms" is correct and usable in written English.
It can be used when referring to something that is available or applicable on multiple platforms, such as software, media, or services.
Example: "The application is designed to work seamlessly across a number of platforms, including Windows, macOS, and Linux."
Alternatives: "on various platforms" or "across multiple platforms".
Over 5.3m app downloads - audiences continue to consume the Guardian across a number of platforms.
We will bear them in mind as we continue to develop our apps across a number of platforms (hint, hint).
Vice's Internet presence is spread across a number of platforms: Web sites, including Vice.com; an ad network; and its YouTube channel, where it repurposes many of its videos.
While Shashi handles all the manufacturing, Sanjay has assumed the role of marketing and PR for the business, promoting the brand across a number of platforms, including Amazon, notonthehighstreet.com and Etsy.
EA are a company responsible for developing and publishing video games across a number of platforms, based in the US, while Nexon develop and publish games for a primarily South Korean audience, with a few titles released worldwide.
Brand extension across a number of platforms is essential to long-term sustainability in this environment.
The Virgance engineering team, headed by VP of Engineering Naseem Hakim (who helped build the very popular Facebook app Circle of Friends), is building a platform designed to help promote these campaigns across a number of social platforms.
Data journalism can take many forms across a number of different platforms, and to reflect this GEN are encouraging organisations and individuals from outside of the traditional media to enter.
Although we sell across a number of online platforms now, including our own dedicated online shop, we have consistently mentioned eBay being the launchpad for our business, which was finally picked up early last year by eBay HQ.
Tenor has long positioned itself as a GIF search tool working across a number of different platforms, ranging from its own keyboard to Facebook Messenger.
Yet a lot of that is very fragmented listening across a number of different platforms, or via other third-party aggregating services like Apple's own iTunes.
