diff --git a/src/Generation/GapicClientV2Generator.php b/src/Generation/GapicClientV2Generator.php
index bf77523b..3cf48e34 100644
--- a/src/Generation/GapicClientV2Generator.php
+++ b/src/Generation/GapicClientV2Generator.php
@@ -414,7 +414,7 @@ private function resourceMethods(): Vector
             return Vector::new();
         }
         $formattedName = AST::param(ResolvedType::string(), AST::var('formattedName'));
-        $template = AST::param(ResolvedType::string(), AST::var('template'), AST::NULL);
+        $template = AST::param(ResolvedType::string(true), AST::var('template'), AST::NULL);
 
         return $this->serviceDetails->resourceParts
             ->map(fn ($x) => $x->getFormatMethod()
diff --git a/src/Utils/ResolvedType.php b/src/Utils/ResolvedType.php
index 983a1d3e..fc0ecf91 100644
--- a/src/Utils/ResolvedType.php
+++ b/src/Utils/ResolvedType.php
@@ -18,6 +18,8 @@
 
 namespace Google\Generator\Utils;
 
+use Closure;
+
 /**
  * Represent a resolved type, ready to use in code output.
  * This class is required to allow a resolved type to be differentiated from other plain strings.
@@ -29,9 +31,9 @@ class ResolvedType
      *
      * @return ResolvedType
      */
-    public static function array(): ResolvedType
+    public static function array(bool $optional = false): ResolvedType
     {
-        return new ResolvedType(Type::array(), fn () => 'array');
+        return new ResolvedType(Type::array(), fn () => 'array', $optional);
     }
 
     /**
@@ -39,9 +41,9 @@ public static function array(): ResolvedType
      *
      * @return ResolvedType
      */
-    public static function string(): ResolvedType
+    public static function string(bool $optional = false): ResolvedType
     {
-        return new ResolvedType(Type::string(), fn () => 'string');
+        return new ResolvedType(Type::string(), fn () => 'string', $optional);
     }
 
     /**
@@ -69,19 +71,16 @@ public static function self(): ResolvedType
      *
      * @param string $typeName The resolved name of the type.
      */
-    public function __construct(Type $type, \Closure $fnToCode)
-    {
-        $this->type = $type;
-        $this->fnToCode = $fnToCode;
+    public function __construct(
+        /** @var Type *Readonly* The type of this resolved-type. */
+        public ReadOnly Type $type,
+        private Closure $fnToCode,
+        private bool $optional = false
+    ) {
     }
 
-    /** @var Type *Readonly* The type of this resolved-type. */
-    public Type $type;
-
-    private \Closure $fnToCode;
-
     public function toCode(): string
     {
-        return ($this->fnToCode)();
+        return ($this->optional ? '?' : '') . ($this->fnToCode)();
     }
 }
diff --git a/tests/Integration/goldens/functions/src/V1/Client/CloudFunctionsServiceClient.php b/tests/Integration/goldens/functions/src/V1/Client/CloudFunctionsServiceClient.php
index 227a91b6..cd4add0e 100644
--- a/tests/Integration/goldens/functions/src/V1/Client/CloudFunctionsServiceClient.php
+++ b/tests/Integration/goldens/functions/src/V1/Client/CloudFunctionsServiceClient.php
@@ -267,14 +267,14 @@ public static function repositoryName(string $project, string $location, string
      * listed, then parseName will check each of the supported templates, and return
      * the first match.
      *
-     * @param string $formattedName The formatted name string
-     * @param string $template      Optional name of template to match
+     * @param string  $formattedName The formatted name string
+     * @param ?string $template      Optional name of template to match
      *
      * @return array An associative array from name component IDs to component values.
      *
      * @throws ValidationException If $formattedName could not be matched.
      */
-    public static function parseName(string $formattedName, string $template = null): array
+    public static function parseName(string $formattedName, ?string $template = null): array
     {
         return self::parseFormattedName($formattedName, $template);
     }
diff --git a/tests/Integration/goldens/redis/src/V1/Client/CloudRedisClient.php b/tests/Integration/goldens/redis/src/V1/Client/CloudRedisClient.php
index d0ace6cc..1e586773 100644
--- a/tests/Integration/goldens/redis/src/V1/Client/CloudRedisClient.php
+++ b/tests/Integration/goldens/redis/src/V1/Client/CloudRedisClient.php
@@ -244,14 +244,14 @@ public static function locationName(string $project, string $location): string
      * listed, then parseName will check each of the supported templates, and return
      * the first match.
      *
-     * @param string $formattedName The formatted name string
-     * @param string $template      Optional name of template to match
+     * @param string  $formattedName The formatted name string
+     * @param ?string $template      Optional name of template to match
      *
      * @return array An associative array from name component IDs to component values.
      *
      * @throws ValidationException If $formattedName could not be matched.
      */
-    public static function parseName(string $formattedName, string $template = null): array
+    public static function parseName(string $formattedName, ?string $template = null): array
     {
         return self::parseFormattedName($formattedName, $template);
     }
diff --git a/tests/Integration/goldens/securitycenter/src/V1/Client/SecurityCenterClient.php b/tests/Integration/goldens/securitycenter/src/V1/Client/SecurityCenterClient.php
index 6fb65850..247ffa02 100644
--- a/tests/Integration/goldens/securitycenter/src/V1/Client/SecurityCenterClient.php
+++ b/tests/Integration/goldens/securitycenter/src/V1/Client/SecurityCenterClient.php
@@ -1233,14 +1233,14 @@ public static function topicName(string $project, string $topic): string
      * listed, then parseName will check each of the supported templates, and return
      * the first match.
      *
-     * @param string $formattedName The formatted name string
-     * @param string $template      Optional name of template to match
+     * @param string  $formattedName The formatted name string
+     * @param ?string $template      Optional name of template to match
      *
      * @return array An associative array from name component IDs to component values.
      *
      * @throws ValidationException If $formattedName could not be matched.
      */
-    public static function parseName(string $formattedName, string $template = null): array
+    public static function parseName(string $formattedName, ?string $template = null): array
     {
         return self::parseFormattedName($formattedName, $template);
     }
diff --git a/tests/Integration/goldens/spanner/src/V1/Client/DatabaseAdminClient.php b/tests/Integration/goldens/spanner/src/V1/Client/DatabaseAdminClient.php
index 6253dbba..7018fdd0 100644
--- a/tests/Integration/goldens/spanner/src/V1/Client/DatabaseAdminClient.php
+++ b/tests/Integration/goldens/spanner/src/V1/Client/DatabaseAdminClient.php
@@ -304,14 +304,14 @@ public static function instanceName(string $project, string $instance): string
      * listed, then parseName will check each of the supported templates, and return
      * the first match.
      *
-     * @param string $formattedName The formatted name string
-     * @param string $template      Optional name of template to match
+     * @param string  $formattedName The formatted name string
+     * @param ?string $template      Optional name of template to match
      *
      * @return array An associative array from name component IDs to component values.
      *
      * @throws ValidationException If $formattedName could not be matched.
      */
-    public static function parseName(string $formattedName, string $template = null): array
+    public static function parseName(string $formattedName, ?string $template = null): array
     {
         return self::parseFormattedName($formattedName, $template);
     }
diff --git a/tests/Unit/ProtoTests/ResourceNames/out/src/Client/ResourceNamesClient.php b/tests/Unit/ProtoTests/ResourceNames/out/src/Client/ResourceNamesClient.php
index 378aa96e..f726cee3 100644
--- a/tests/Unit/ProtoTests/ResourceNames/out/src/Client/ResourceNamesClient.php
+++ b/tests/Unit/ProtoTests/ResourceNames/out/src/Client/ResourceNamesClient.php
@@ -421,14 +421,14 @@ public static function wildcardMultiPatternName(string $item1Id): string
      * listed, then parseName will check each of the supported templates, and return
      * the first match.
      *
-     * @param string $formattedName The formatted name string
-     * @param string $template      Optional name of template to match
+     * @param string  $formattedName The formatted name string
+     * @param ?string $template      Optional name of template to match
      *
      * @return array An associative array from name component IDs to component values.
      *
      * @throws ValidationException If $formattedName could not be matched.
      */
-    public static function parseName(string $formattedName, string $template = null): array
+    public static function parseName(string $formattedName, ?string $template = null): array
     {
         return self::parseFormattedName($formattedName, $template);
     }