Abstract: According to certain implementations, a certificate management service of a cloud service provider requests a certificate for a domain from a certificate authority utilizing an HTTP-based challenge. The certificate authority responds with a challenge string and a subdirectory within the domain. The challenge string and subdirectory within the domain are sent from the certificate management service to a proxy server of the cloud service provider that manages a flow of data to a host that hosts the domain. When the certificate authority sends a request to the sub directory within the domain, the request is intercepted at the proxy server. Instead of forwarding the request to the host that hosts the domain, the proxy server responds to the certificate authority with the challenge string. This verifies ownership of the domain, which is required to obtain the certificate for the domain.