How long to detect NS don't point to CF anymore?

I’ve been doing some testing with the API and Cloudflare appears to be pretty fast at detecting once a domain has its nameservers pointed to Cloudflare.

But when a domain changes its nameservers to a different provider, how long does it take Cloudflare to recognize that?

I add a domain, pointed the domain to CF and it detected that within about 10 minutes. I then switched the nameservers to a different DNS provider. But about 18 hours later Cloudflare still lists it as active in the dashboard and API.

I’ve tried using Zone Details and Zone Activation Check in the API to detect that it’s no longer pointed to Cloudflare but both keep saying it’s active.

I couldn’t find anything in any docs that stated how often they check to see if a zone is still active. Also, I wasn’t sure if they set a minimum time that it has to be pointed away for it to be marked as inactive. For example, maybe someone didn’t notice the nameservers changed due to it expiring, but maybe CF wants to give them 2-3 days to fix it before marking it as inactive…

It seems to take at least a week, but it shouldn’t affect anything. Once you change name servers away from Cloudflare, that change should be fully in effect within 48 hours. You probably don’t want Cloudflare dropping your zone just because you temporarily changed name servers. It’s a gradual exit. Again, it shouldn’t affect anything if you intend to move away from Cloudflare.