Quoting Terms of Service:
SECTION 10: LIMITATION ON NON-HTML CACHING
You acknowledge that Cloudflare’s Service is offered as a platform to cache and serve web pages and websites and is not offered for other purposes, such as remote storage. Accordingly, you understand and agree to use the Service solely for the purpose of hosting and serving web pages as viewed through a web browser or other application and the Hypertext Markup Language (HTML) protocol or other equivalent technology. Cloudflare’s Service is also a shared web caching service, which means a number of customers’ websites are cached from the same server. To ensure that Cloudflare’s Service is reliable and available for the greatest number of users, a customer’s usage cannot adversely affect the performance of other customers’ sites. Additionally, the purpose of Cloudflare’s Service is to proxy web content, not store data. Using an account primarily as an online storage space, including the storage or caching of a disproportionate percentage of pictures, movies, audio files, or other non-HTML content, is prohibited. You further agree that if, at Cloudflare’s sole discretion, you are deemed to have violated this section, or if Cloudflare, in its sole discretion, deems it necessary due to excessive burden or potential adverse impact on Cloudflare’s systems, potential adverse impact on other users, server processing power, server memory, abuse controls, or other reasons, Cloudflare may suspend or terminate your account without notice to or liability to you.
Does that mean I should not proxy my APIs and downloads (max download size is ~150MB) through CloudFlare? My website will include a web app which allows people to upload their mods for computer games and a forum, and will also accept requests to API and downloads from an app installed by the users that installs the downloaded mods. I planned to use Pro plan ($20/mo). Is such an app allowed to be used?