I recently published a plugin to integrate Cloudflare R2 with Craft CMS. After having a chance to utilize this on a few more projects after its release, I wanted to put together a guide to streamline this process for future use cases. Hopefully this will help out any others out there looking to setup R2 on their Cloudflare accounts, as most of this won't be specific to Craft CMS.
When a website required limited access, I needed a way to lock it down to specific physical devices. I couldn't rely on IP addresses which might change regularly, and while a strong password requirement might be sufficient I wanted something a little more secure. Not to mention that it shouldn't be crawled by any search engines either. The solution was a Cloudflare client certificate and mTLS firewall rule.