Another non-obvious Cloudflare default, not billing but just as silent: if the "Browser Integrity Check" is enabled by default, your API behind Cloudflare will return a 403 error for requests with the `Python-urllib` User-Agent. However, you won't see this in your server logs (these events appear only under Cloudflare > Security > Events). From your perspective, it will look as though these clients simply aren't accessing the API. You can fix this by turning off "Browser Integrity Check" (under Security > Settings) or by creating a rule to exclude API paths from the check.