Note: I am not your lawyer, and I am not Cloudflare’s lawyer.
Unless otherwise expressly permitted in writing by Cloudflare, you will not and you have no right to:
(a) rent, lease, loan, export, or sell access to the Cloud Services to any third party;
Assuming your agreement with your clients gives you whatever permission to change your client’s nameservers to
something.ns.cloudflare.com and you tell them they’re going to use Cloudflare, you probably won’t be violating this section of the self-serve terms. “sell” is ambiguous on purpose but I would suspect it’s not widely enforced; many people here manage client websites without issue.
If you want to stay on the safe, your best setup would be:
- have the client sign up for Cloudflare
- client sets up their own credit card in Cloudflare for billing
- client invites you as an admin on the account (via the members page) (or they provide you their API Token/API key)
- they or you add their domain(s) and you can perform your services as you wish
This would put your relative position as simply selling your expertise in managing Cloudflare sites, not reselling the service.