diff --git a/CHANGELOG.md b/CHANGELOG.md
index f508ae06a9..5148febfeb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,7 @@
     * Set minimum requirements to [PHP 5.6.4](https://getgrav.org/blog/raising-php-requirements-2018)
     * Updated Doctrine Collections to 1.4
     * Updated Symfony Components to 3.4 (with compatibility mode to fall back to Symfony YAML 2.8)
-    * Added new `Grav\Framework\File\Formatter` classes for encoding/decoding YAML, MarkDown, JSON, INI and PHP serialized formats
+    * Added new `Grav\Framework\File\Formatter` classes for encoding/decoding YAML, Markdown, JSON, INI and PHP serialized strings
 
 # v1.4.4
 ## 04/12/2018
diff --git a/system/src/Grav/Framework/File/Formatter/FormatterInterface.php b/system/src/Grav/Framework/File/Formatter/FormatterInterface.php
index 55c9b950d3..1fc2afae85 100644
--- a/system/src/Grav/Framework/File/Formatter/FormatterInterface.php
+++ b/system/src/Grav/Framework/File/Formatter/FormatterInterface.php
@@ -10,6 +10,13 @@
 
 interface FormatterInterface
 {
+    /**
+     * Get file extension with dot.
+     *
+     * @return string
+     */
+    public function getFileExtension();
+
     /**
      * Encode data into a string.
      *
diff --git a/system/src/Grav/Framework/File/Formatter/IniFormatter.php b/system/src/Grav/Framework/File/Formatter/IniFormatter.php
index 38d9014dba..ff6d99fd62 100644
--- a/system/src/Grav/Framework/File/Formatter/IniFormatter.php
+++ b/system/src/Grav/Framework/File/Formatter/IniFormatter.php
@@ -14,9 +14,26 @@
  */
 class IniFormatter implements FormatterInterface
 {
+    /** @var array */
+    private $config;
+
+    /**
+     * IniFormatter constructor.
+     * @param array $config
+     */
+    public function __construct(array $config = [])
+    {
+        $this->config = $config + [
+                'file_extension' => '.ini'
+            ];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
     public function getFileExtension()
     {
-        return 'ini';
+        return $this->config['file_extension'];
     }
 
     /**
@@ -32,6 +49,7 @@ public function encode($data)
                     $value
                 ) . "\"\n";
         }
+
         return $string;
     }
 
@@ -43,7 +61,7 @@ public function decode($data)
         $decoded = @parse_ini_string($data);
 
         if ($decoded === false) {
-            throw new \RuntimeException("Decoding INI format failed'");
+            throw new \RuntimeException('Decoding INI failed');
         }
 
         return $decoded;
diff --git a/system/src/Grav/Framework/File/Formatter/JsonFormatter.php b/system/src/Grav/Framework/File/Formatter/JsonFormatter.php
index 0808fdea6a..227bd5b8f6 100644
--- a/system/src/Grav/Framework/File/Formatter/JsonFormatter.php
+++ b/system/src/Grav/Framework/File/Formatter/JsonFormatter.php
@@ -20,14 +20,18 @@ class JsonFormatter implements FormatterInterface
     public function __construct(array $config = [])
     {
         $this->config = $config + [
+            'file_extension' => '.json',
             'encode_options' => 0,
             'decode_assoc' => true
         ];
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function getFileExtension()
     {
-        return 'json';
+        return $this->config['file_extension'];
     }
 
     /**
@@ -35,10 +39,13 @@ public function getFileExtension()
      */
     public function encode($data)
     {
-        $encoded = json_encode($data, $this->config['encode_options']);
+        $encoded = @json_encode($data, $this->config['encode_options']);
+
         if ($encoded === false) {
-            throw new \RuntimeException('');
+            throw new \RuntimeException('Encoding JSON failed');
         }
+
+        return $encoded;
     }
 
     /**
@@ -46,6 +53,12 @@ public function encode($data)
      */
     public function decode($data)
     {
-        return json_decode($data, $this->config['decode_assoc']);
+        $decoded = @json_decode($data, $this->config['decode_assoc']);
+
+        if ($decoded === false) {
+            throw new \RuntimeException('Decoding JSON failed');
+        }
+
+        return $decoded;
     }
 }
diff --git a/system/src/Grav/Framework/File/Formatter/MarkdownFormatter.php b/system/src/Grav/Framework/File/Formatter/MarkdownFormatter.php
index 49e82fc21d..3d5c55b8ff 100644
--- a/system/src/Grav/Framework/File/Formatter/MarkdownFormatter.php
+++ b/system/src/Grav/Framework/File/Formatter/MarkdownFormatter.php
@@ -22,6 +22,7 @@ class MarkdownFormatter implements FormatterInterface
     public function __construct(array $config = [], FormatterInterface $headerFormatter = null)
     {
         $this->config = $config + [
+            'file_extension' => '.md',
             'header' => 'header',
             'body' => 'markdown',
             'raw' => 'frontmatter',
@@ -31,9 +32,12 @@ public function __construct(array $config = [], FormatterInterface $headerFormat
         $this->headerFormatter = $headerFormatter ?: new YamlFormatter($this->config['formatter']);
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function getFileExtension()
     {
-        return 'md';
+        return $this->config['file_extension'];
     }
 
     /**
diff --git a/system/src/Grav/Framework/File/Formatter/SerializeFormatter.php b/system/src/Grav/Framework/File/Formatter/SerializeFormatter.php
index 7e4894b927..1662dfee6e 100644
--- a/system/src/Grav/Framework/File/Formatter/SerializeFormatter.php
+++ b/system/src/Grav/Framework/File/Formatter/SerializeFormatter.php
@@ -10,9 +10,26 @@
 
 class SerializeFormatter implements FormatterInterface
 {
+    /** @var array */
+    private $config;
+
+    /**
+     * IniFormatter constructor.
+     * @param array $config
+     */
+    public function __construct(array $config = [])
+    {
+        $this->config = $config + [
+                'file_extension' => '.ser'
+            ];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
     public function getFileExtension()
     {
-        return 'raw';
+        return $this->config['file_extension'];
     }
 
     /**
@@ -28,7 +45,13 @@ public function encode($data)
      */
     public function decode($data)
     {
-        return $this->preserveLines(unserialize($data), ['\\n', '\\r'], ["\n", "\r"]);
+        $decoded = @unserialize($data);
+
+        if ($decoded === false) {
+            throw new \RuntimeException('Decoding serialized data failed');
+        }
+
+        return $this->preserveLines($decoded, ['\\n', '\\r'], ["\n", "\r"]);
     }
 
     /**
diff --git a/system/src/Grav/Framework/File/Formatter/YamlFormatter.php b/system/src/Grav/Framework/File/Formatter/YamlFormatter.php
index 662843886b..6c80d99ee2 100644
--- a/system/src/Grav/Framework/File/Formatter/YamlFormatter.php
+++ b/system/src/Grav/Framework/File/Formatter/YamlFormatter.php
@@ -25,6 +25,7 @@ class YamlFormatter implements FormatterInterface
     public function __construct(array $config = [])
     {
         $this->config = $config + [
+            'file_extension' => '.yaml',
             'inline' => 5,
             'indent' => 2,
             'native' => true,
@@ -32,9 +33,12 @@ public function __construct(array $config = [])
         ];
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function getFileExtension()
     {
-        return 'yaml';
+        return $this->config['file_extension'];
     }
 
     /**
@@ -50,7 +54,7 @@ public function encode($data)
                 YamlParser::DUMP_EXCEPTION_ON_INVALID_TYPE
             );
         } catch (DumpException $e) {
-            throw new \RuntimeException($e->getMessage(), 500, $e);
+            throw new \RuntimeException('Encoding YAML failed: ' . $e->getMessage(), 0, $e);
         }
     }
 
@@ -79,7 +83,7 @@ public function decode($data)
                 return (array) FallbackYamlParser::parse($data);
             }
 
-            throw new \RuntimeException($e->getMessage(), 500, $e);
+            throw new \RuntimeException('Decoding YAML failed: ' . $e->getMessage(), 0, $e);
         }
     }
 }