Cloudflare is excellent choice for delivery network and DDoS protection.
The Quizier is built using Laravel and we use the in system cache to maximize the performance of your site. If you want to use Cloudflare for your Quizier site then it should work fine but do not cache pages as static on Cloudflare, because for XSS protection Quizier use a token that is sent in every post request (i.e. Login page, Reaction, Comment and all action where user of your site is sending data to your server) when you Cache your page on Cloudflare then the token remains same and ultimately your site users will see Page Expired error on every post request.
If you are using Cloudflare for CDN and DDoS protection then there is no issue.
How to disable Cloudflare Cache.
By default Cloudflare will not cache your pages as static, this is something that you do in the Cloudflare page rules, just make sure you do not add Cache page rules. :)