I've noticed that the "Expect-CT" header is present in the requests made to my website, but I'm unsure which service is responsible for adding this header. I'm particularly interested in determining whether it is Vercel or Cloudflare that is injecting the "Expect-CT" header into the requests.
this is the error from Google Pagespeed service (Lighthouse).
Uses deprecated APIs:
Expect-CT header is deprecated and will be removed. Chrome requires Certificate Transparency for all publicly trusted certificates issued after April 30, 2018.Could someone clear it for the origin of the "Expect-CT" header in website requests? Is it added automatically by Vercel or Cloudflare, or do I need to configure it explicitly in one of these services? If it's automatically added, can I customize its settings or disable it if necessary?
Most likely this header is coming from CloudFlare. I do not see the "Expect-CT" header on my websites hosted on Vercel.
Please see if the solution described in the following discussion is applicable in your case.
https://community.cloudflare.com/t/deprecated-expect-ct-header/485737