Conceptually WACS works by chaining together five components, which can be 'mixed and matched' to support many use cases.

1. A target plugin provides information about (potential) certificates to create.
2. A validation plugin provides the ACME server with proof that you own the domains(s).
3. A CSR plugin determines the (type of) private key and extensions to use for the certificate.
4. One or more store plugins place the certificate in a specific location and format.
5. One or more install plugins make changes to your application(s) configuration.

Those interested in developing their own plugin for any of the five stages should start by reading about the architecture.