diff --git a/src/Dockerfile.php b/src/Dockerfile.php
index 6308ad4..59f85f8 100644
--- a/src/Dockerfile.php
+++ b/src/Dockerfile.php
@@ -12,7 +12,7 @@ final class Dockerfile implements \IteratorAggregate, \Countable, FileInterface,
     /** @var iterable|Dockerfile\LayerInterface[] */
     private iterable $layers;
 
-    public function __construct(null|LayerInterface ...$layers)
+    public function __construct(?LayerInterface ...$layers)
     {
         $this->layers = $layers;
     }
diff --git a/src/PHP/ComposerGithubOauthAuthentication.php b/src/PHP/ComposerGithubOauthAuthentication.php
index c5a260e..1c34ce2 100644
--- a/src/PHP/ComposerGithubOauthAuthentication.php
+++ b/src/PHP/ComposerGithubOauthAuthentication.php
@@ -10,6 +10,7 @@
 {
     public function __construct(
         private string $token,
+        private string $domain = 'github.com',
     ) {
     }
 
@@ -17,7 +18,7 @@ public function __toString(): string
     {
         return (string) new Dockerfile\Run(sprintf(<<<'RUN'
             set -ex \
-                && composer config --auth github-oauth.github.com %s
-            RUN, $this->token));
+                && composer config --auth github-oauth.%s %s
+            RUN, $this->domain, $this->token));
     }
 }
diff --git a/src/PHP/ComposerGitlabOauthAuthentication.php b/src/PHP/ComposerGitlabOauthAuthentication.php
index 857f419..03cdb61 100644
--- a/src/PHP/ComposerGitlabOauthAuthentication.php
+++ b/src/PHP/ComposerGitlabOauthAuthentication.php
@@ -10,7 +10,7 @@
 {
     public function __construct(
         private string $token,
-        private string $instance = 'gitlab.com',
+        private string $domain = 'gitlab.com',
     ) {
     }
 
@@ -19,6 +19,6 @@ public function __toString(): string
         return (string) new Dockerfile\Run(sprintf(<<<'RUN'
             set -ex \
                 && composer config --auth gitlab-oauth.%s %s
-            RUN, $this->instance, $this->token));
+            RUN, $this->domain, $this->token));
     }
 }
diff --git a/src/PHP/ComposerGitlabTokenAuthentication.php b/src/PHP/ComposerGitlabTokenAuthentication.php
index 55e3437..bd8414e 100644
--- a/src/PHP/ComposerGitlabTokenAuthentication.php
+++ b/src/PHP/ComposerGitlabTokenAuthentication.php
@@ -10,7 +10,7 @@
 {
     public function __construct(
         private string $token,
-        private string $instance = 'gitlab.com',
+        private string $domain = 'gitlab.com',
     ) {
     }
 
@@ -19,6 +19,6 @@ public function __toString(): string
         return (string) new Dockerfile\Run(sprintf(<<<'RUN'
             set -ex \
                 && composer config --auth gitlab-token.%s %s
-            RUN, $this->instance, $this->token));
+            RUN, $this->domain, $this->token));
     }
 }
diff --git a/src/PHP/ComposerHttpBasicAuthentication.php b/src/PHP/ComposerHttpBasicAuthentication.php
index 9e733fc..b670442 100644
--- a/src/PHP/ComposerHttpBasicAuthentication.php
+++ b/src/PHP/ComposerHttpBasicAuthentication.php
@@ -9,7 +9,7 @@
 final readonly class ComposerHttpBasicAuthentication implements Dockerfile\LayerInterface, \Stringable
 {
     public function __construct(
-        private string $url,
+        private string $domain,
         private string $username,
         private string $password,
     ) {
@@ -20,6 +20,6 @@ public function __toString(): string
         return (string) new Dockerfile\Run(sprintf(<<<'RUN'
             set -ex \
                 && composer config --auth http-basic.%s %s %s
-            RUN, $this->url, $this->username, $this->password));
+            RUN, $this->domain, $this->username, $this->password));
     }
 }
diff --git a/src/PHP/ComposerHttpBearerAuthentication.php b/src/PHP/ComposerHttpBearerAuthentication.php
index acfa265..dd4f74d 100644
--- a/src/PHP/ComposerHttpBearerAuthentication.php
+++ b/src/PHP/ComposerHttpBearerAuthentication.php
@@ -9,7 +9,7 @@
 final readonly class ComposerHttpBearerAuthentication implements Dockerfile\LayerInterface, \Stringable
 {
     public function __construct(
-        private string $url,
+        private string $domain,
         private string $token,
     ) {
     }
@@ -19,6 +19,6 @@ public function __toString(): string
         return (string) new Dockerfile\Run(sprintf(<<<'RUN'
             set -ex \
                 && composer config --auth bearer.%s %s
-            RUN, $this->url, $this->token));
+            RUN, $this->domain, $this->token));
     }
 }