diff --git a/roles/certbot/README.md b/roles/certbot/README.md
index ccb687b..3ad35bf 100644
--- a/roles/certbot/README.md
+++ b/roles/certbot/README.md
@@ -9,10 +9,10 @@ Also see the following documentation for a full How-to on how to get certificate
 ## Required Arguments
 
 - `certbot__acme_account_email_address`: The E-Mail address to use for the ACME account.
-- `certbot__certificate_domains`: The domains for which to obtain a certificate.
 
 ## Optional Arguments
 
+- `certbot__certificate_domains`: The domains for which to obtain a certificate using the HTTP-01 challenge.
 - `certbot__http_01_port`: The port number the bot listens on. Should be `80` if directly exposed to the internet.  
    Defaults to `31820` (for the public-reverse-proxy setup).
 - `certbot__new_cert_commands`: A list of commands to execute after getting a new certificate. Will be added into a bash script.  
diff --git a/roles/certbot/defaults/main.yaml b/roles/certbot/defaults/main.yaml
index 9b20634..9e6551e 100644
--- a/roles/certbot/defaults/main.yaml
+++ b/roles/certbot/defaults/main.yaml
@@ -1,2 +1,3 @@
+certbot__certificate_domains: [ ]
 certbot__http_01_port: 31820
 certbot__new_cert_commands: [ ]
diff --git a/roles/certbot/meta/argument_specs.yaml b/roles/certbot/meta/argument_specs.yaml
index c8b45dd..b895b5f 100644
--- a/roles/certbot/meta/argument_specs.yaml
+++ b/roles/certbot/meta/argument_specs.yaml
@@ -7,7 +7,8 @@ argument_specs:
       certbot__certificate_domains:
         type: list
         elements: str
-        required: true
+        required: false
+        default: [ ]
       certbot__http_01_port:
         type: str
         required: false