diff --git a/src/JsonDecoder.php b/src/JsonDecoder.php
index c5a75f8..fa270f7 100644
--- a/src/JsonDecoder.php
+++ b/src/JsonDecoder.php
@@ -106,17 +106,17 @@ public function decode($json, $schema = null)
             );
         }
 
-        $decoded = $this->decodeJson($json);
+        $data = $this->decodeJson($json);
 
-        if (null !== $schema) {
-            $errors = $this->validator->validate($decoded, $schema);
+        if (null !== $schema || isset($data->{'$schema'})) {
+            $errors = $this->validator->validate($data, $schema);
 
             if (count($errors) > 0) {
                 throw ValidationFailedException::fromErrors($errors);
             }
         }
 
-        return $decoded;
+        return $data;
     }
 
     /**
diff --git a/src/JsonEncoder.php b/src/JsonEncoder.php
index fc7b30a..dba8c63 100644
--- a/src/JsonEncoder.php
+++ b/src/JsonEncoder.php
@@ -130,7 +130,7 @@ public function __construct(JsonValidator $validator = null)
      */
     public function encode($data, $schema = null)
     {
-        if (null !== $schema) {
+        if (null !== $schema || isset($data->{'$schema'})) {
             $errors = $this->validator->validate($data, $schema);
 
             if (count($errors) > 0) {