ACME briefly explained

ACME (Automatic Certificate Management Environment, RFC 8555) is an open internet protocol. With ACME, software orders, renews and revokes certificates at a certification authority (CA) fully automatically. Instead of a person filling in a form, TLSPilot proves by itself that you control the domain, for example with a DNS entry or a file on the web server. Let’s Encrypt made ACME popular. Today, Google Trust Services, ZeroSSL, Sectigo, DigiCert and other CAs also offer ACME.

TLSPilot does all of this for you: it registers the ACME account, orders the certificate, proves control of every name with DNS-01, HTTP-01 or TLS-ALPN-01, downloads the certificate with its chain and renews it in time in its renewal window. If the CA offers ACME Renewal Information (ARI), TLSPilot follows the window of the CA. You only select the ACME provider and the challenge type and, depending on the type, the DNS provider and the DNS credential or the web root, see chapter ACME certificate (AC).

How ACME, ARI, ACME profiles, the challenge types, CAA records, multi-perspective validation and DNS-01 Alias Mode work in detail is explained in chapter ACME in depth: validation, renewal and DNS.