diff --git a/composer.json b/composer.json
index 4a893b1..aad4fb6 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,8 @@
     ],
     "require": {
         "php": ">=5.6",
-        "ext-curl": "*"
+        "ext-curl": "*",
+        "ext-json": "*"
     },
     "autoload" : {
         "files": ["source/paysafe.php"]
diff --git a/source/Paysafe/JSONObject.php b/source/Paysafe/JSONObject.php
index ef3a8ce..c10586a 100644
--- a/source/Paysafe/JSONObject.php
+++ b/source/Paysafe/JSONObject.php
@@ -21,7 +21,9 @@
 
 namespace Paysafe;
 
-class JSONObject {
+use JsonSerializable;
+
+class JSONObject implements JsonSerializable{
 
     protected static $fieldTypes = array();
     private $properties = array();
@@ -37,7 +39,7 @@ public function setOptionalFields($fields) {
         if (!is_array($fields)) {
             throw new PaysafeException('Invalid optional fields. Array expected.');
         }
-        if (($diff = array_diff($fields, array_keys(static::$fieldTypes)))) {
+        if ($diff = array_diff($fields, array_keys(static::$fieldTypes))) {
             throw new PaysafeException('Invalid optional fields. Unknown fields: ' . join(', ', $diff));
         }
 
@@ -202,7 +204,8 @@ private function cast($name, $value, $type) {
 
     /**
      *
-     * @return json encoded copy of this object
+     * @return string|false encoded copy of this object
+     * @throws PaysafeException
      */
     public function toJson() {
         return json_encode($this->jsonSerialize());
@@ -225,7 +228,7 @@ final public function jsonSerialize() {
     }
 
     public function checkRequiredFields() {
-        if (($diff = array_diff($this->requiredFields, array_keys($this->properties)))) {
+        if ($diff = array_diff($this->requiredFields, array_keys($this->properties))) {
             throw new PaysafeException('Missing required properties: ' . join(', ', $diff), 500);
         }
     }
diff --git a/tests/paysafe/MerchantAccountServiceTest.php b/tests/paysafe/MerchantAccountServiceTest.php
index a80d749..a8b84cb 100644
--- a/tests/paysafe/MerchantAccountServiceTest.php
+++ b/tests/paysafe/MerchantAccountServiceTest.php
@@ -101,7 +101,7 @@ public function testCreateMerchantAccountMissingRequiredFields()
 
         $this->expectException(PaysafeException::class);
         $this->expectExceptionCode(500);
-        $this->expectExceptionMessage('Missing required properties: name, currency, region, legalEntity, productCode, category, phone, yearlyVolumeRange, averageTransactionAmount, merchantDescriptor, caAccountDetails');
+        $this->expectExceptionMessage('Missing required properties: name, currency, region, legalEntity, productCode, category, phone, yearlyVolumeRange, averageTransactionAmount, merchantDescriptor');
 
         $mas->createMerchantAccount(new MerchantAccount());
     }