diff --git a/.gitignore b/.gitignore
index 7b39a0b..5cbf483 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,5 @@ vendor
 downloads
 .idea/*
 tests/.phpunit.result.cache
+/rector.php
+/.vs
diff --git a/downloads/httpful.phar b/downloads/httpful.phar
new file mode 100644
index 0000000..5e0d600
Binary files /dev/null and b/downloads/httpful.phar differ
diff --git a/src/Httpful/Bootstrap.php b/src/Httpful/Bootstrap.php
index 9974bcf..6665fd5 100644
--- a/src/Httpful/Bootstrap.php
+++ b/src/Httpful/Bootstrap.php
@@ -11,8 +11,8 @@
 class Bootstrap
 {
 
-    const DIR_GLUE = DIRECTORY_SEPARATOR;
-    const NS_GLUE = '\\';
+    public const DIR_GLUE = DIRECTORY_SEPARATOR;
+    public const NS_GLUE = '\\';
 
     public static $registered = false;
 
@@ -21,7 +21,7 @@ class Bootstrap
      */
     public static function init()
     {
-        spl_autoload_register(array('\Httpful\Bootstrap', 'autoload'));
+        spl_autoload_register(['\\' . \Httpful\Bootstrap::class, 'autoload']);
         self::registerHandlers();
     }
 
@@ -32,7 +32,7 @@ public static function init()
      */
     public static function autoload($classname)
     {
-        self::_autoload(dirname(dirname(__FILE__)), $classname);
+        self::_autoload(dirname(__FILE__,2), $classname);
     }
 
     /**
@@ -40,7 +40,7 @@ public static function autoload($classname)
      */
     public static function pharInit()
     {
-        spl_autoload_register(array('\Httpful\Bootstrap', 'pharAutoload'));
+        spl_autoload_register(['\\' . \Httpful\Bootstrap::class, 'pharAutoload']);
         self::registerHandlers();
     }
 
@@ -78,12 +78,12 @@ public static function registerHandlers()
 
         // @todo check a conf file to load from that instead of
         // hardcoding into the library?
-        $handlers = array(
+        $handlers = [
             \Httpful\Mime::JSON => new \Httpful\Handlers\JsonHandler(),
             \Httpful\Mime::XML  => new \Httpful\Handlers\XmlHandler(),
             \Httpful\Mime::FORM => new \Httpful\Handlers\FormHandler(),
             \Httpful\Mime::CSV  => new \Httpful\Handlers\CsvHandler(),
-        );
+        ];
 
         foreach ($handlers as $mime => $handler) {
             // Don't overwrite if the handler has already been registered
diff --git a/src/Httpful/Handlers/CsvHandler.php b/src/Httpful/Handlers/CsvHandler.php
index de7b15b..69c79d0 100644
--- a/src/Httpful/Handlers/CsvHandler.php
+++ b/src/Httpful/Handlers/CsvHandler.php
@@ -18,13 +18,13 @@ public function parse($body)
         if (empty($body))
             return null;
 
-        $parsed = array();
+        $parsed = [];
         $fp = fopen('data://text/plain;base64,' . base64_encode($body), 'r');
         while (($r = fgetcsv($fp)) !== FALSE) {
             $parsed[] = $r;
         }
 
-        if (empty($parsed))
+        if ($parsed === [])
             throw new \Exception("Unable to parse response as CSV");
         return $parsed;
     }
@@ -33,7 +33,7 @@ public function parse($body)
      * @param mixed $payload
      * @return string
      */
-    public function serialize($payload)
+    public function serialize($payload): string
     {
         $fp = fopen('php://temp/maxmemory:'. (6*1024*1024), 'r+');
         $i = 0;
diff --git a/src/Httpful/Handlers/FormHandler.php b/src/Httpful/Handlers/FormHandler.php
index fea1c37..0ff05a8 100644
--- a/src/Httpful/Handlers/FormHandler.php
+++ b/src/Httpful/Handlers/FormHandler.php
@@ -14,7 +14,7 @@ class FormHandler extends MimeHandlerAdapter
      */
     public function parse($body)
     {
-        $parsed = array();
+        $parsed = [];
         parse_str($body, $parsed);
         return $parsed;
     }
@@ -23,7 +23,7 @@ public function parse($body)
      * @param mixed $payload
      * @return string
      */
-    public function serialize($payload)
+    public function serialize($payload): string
     {
         return http_build_query($payload, null, '&');
     }
diff --git a/src/Httpful/Handlers/JsonHandler.php b/src/Httpful/Handlers/JsonHandler.php
index 6166283..414a728 100644
--- a/src/Httpful/Handlers/JsonHandler.php
+++ b/src/Httpful/Handlers/JsonHandler.php
@@ -14,7 +14,7 @@ class JsonHandler extends MimeHandlerAdapter
 
     public function init(array $args)
     {
-        $this->decode_as_array = !!(array_key_exists('decode_as_array', $args) ? $args['decode_as_array'] : false);
+        $this->decode_as_array = (bool) ($args['decode_as_array'] ?? false);
     }
 
     /**
@@ -37,7 +37,7 @@ public function parse($body)
      * @param mixed $payload
      * @return string
      */
-    public function serialize($payload)
+    public function serialize($payload): string
     {
         return json_encode($payload);
     }
diff --git a/src/Httpful/Handlers/MimeHandlerAdapter.php b/src/Httpful/Handlers/MimeHandlerAdapter.php
index e57ebb0..53e04ad 100644
--- a/src/Httpful/Handlers/MimeHandlerAdapter.php
+++ b/src/Httpful/Handlers/MimeHandlerAdapter.php
@@ -10,7 +10,7 @@
 
 class MimeHandlerAdapter
 {
-    public function __construct(array $args = array())
+    public function __construct(array $args = [])
     {
         $this->init($args);
     }
@@ -36,18 +36,18 @@ public function parse($body)
      * @param mixed $payload
      * @return string
      */
-    function serialize($payload)
+    function serialize($payload): string
     {
         return (string) $payload;
     }
 
-    protected function stripBom($body)
+    protected function stripBom($body): string
     {
         if ( substr($body,0,3) === "\xef\xbb\xbf" )  // UTF-8
             $body = substr($body,3);
-        else if ( substr($body,0,4) === "\xff\xfe\x00\x00" || substr($body,0,4) === "\x00\x00\xfe\xff" )  // UTF-32
+        elseif ( substr($body,0,4) === "\xff\xfe\x00\x00" || substr($body,0,4) === "\x00\x00\xfe\xff" )  // UTF-32
             $body = substr($body,4);
-        else if ( substr($body,0,2) === "\xff\xfe" || substr($body,0,2) === "\xfe\xff" )  // UTF-16
+        elseif ( substr($body,0,2) === "\xff\xfe" || substr($body,0,2) === "\xfe\xff" )  // UTF-16
             $body = substr($body,2);
         return $body;
     }
diff --git a/src/Httpful/Handlers/XmlHandler.php b/src/Httpful/Handlers/XmlHandler.php
index 9298a1f..fb8d2b2 100644
--- a/src/Httpful/Handlers/XmlHandler.php
+++ b/src/Httpful/Handlers/XmlHandler.php
@@ -23,10 +23,10 @@ class XmlHandler extends MimeHandlerAdapter
     /**
      * @param array $conf sets configuration options
      */
-    public function __construct(array $conf = array())
+    public function __construct(array $conf = [])
     {
-        $this->namespace =      isset($conf['namespace']) ? $conf['namespace'] : '';
-        $this->libxml_opts =    isset($conf['libxml_opts']) ? $conf['libxml_opts'] : 0;
+        $this->namespace =      $conf['namespace'] ?? '';
+        $this->libxml_opts =    $conf['libxml_opts'] ?? 0;
     }
 
     /**
@@ -50,9 +50,9 @@ public function parse($body)
      * @return string
      * @throws \Exception if unable to serialize
      */
-    public function serialize($payload)
+    public function serialize($payload): string
     {
-        list($_, $dom) = $this->_future_serializeAsXml($payload);
+        [$_, $dom] = $this->_future_serializeAsXml($payload);
         return $dom->saveXml();
     }
 
@@ -61,7 +61,7 @@ public function serialize($payload)
      * @return string
      * @author Ted Zellers
      */
-    public function serialize_clean($payload)
+    public function serialize_clean($payload): string
     {
         $xml = new \XMLWriter;
         $xml->openMemory();
@@ -75,7 +75,7 @@ public function serialize_clean($payload)
      * @param mixed $node to serialize
      * @author Ted Zellers
      */
-    public function serialize_node(&$xmlw, $node){
+    public function serialize_node(&$xmlw, $node) {
         if (!is_array($node)){
             $xmlw->text($node);
         } else {
@@ -90,7 +90,7 @@ public function serialize_node(&$xmlw, $node){
     /**
      * @author Zack Douglas <zack@zackerydouglas.info>
      */
-    private function _future_serializeAsXml($value, $node = null, $dom = null)
+    private function _future_serializeAsXml($value, $node = null, $dom = null): array
     {
         if (!$dom) {
             $dom = new \DOMDocument;
@@ -107,21 +107,21 @@ private function _future_serializeAsXml($value, $node = null, $dom = null)
             $objNode = $dom->createElement(get_class($value));
             $node->appendChild($objNode);
             $this->_future_serializeObjectAsXml($value, $objNode, $dom);
-        } else if (is_array($value)) {
+        } elseif (is_array($value)) {
             $arrNode = $dom->createElement('array');
             $node->appendChild($arrNode);
             $this->_future_serializeArrayAsXml($value, $arrNode, $dom);
-        } else if (is_bool($value)) {
+        } elseif (is_bool($value)) {
             $node->appendChild($dom->createTextNode($value?'TRUE':'FALSE'));
         } else {
             $node->appendChild($dom->createTextNode($value));
         }
-        return array($node, $dom);
+        return [$node, $dom];
     }
     /**
      * @author Zack Douglas <zack@zackerydouglas.info>
      */
-    private function _future_serializeArrayAsXml($value, &$parent, &$dom)
+    private function _future_serializeArrayAsXml($value, &$parent, &$dom): array
     {
         foreach ($value as $k => &$v) {
             $n = $k;
@@ -132,12 +132,12 @@ private function _future_serializeArrayAsXml($value, &$parent, &$dom)
             $parent->appendChild($el);
             $this->_future_serializeAsXml($v, $el, $dom);
         }
-        return array($parent, $dom);
+        return [$parent, $dom];
     }
     /**
      * @author Zack Douglas <zack@zackerydouglas.info>
      */
-    private function _future_serializeObjectAsXml($value, &$parent, &$dom)
+    private function _future_serializeObjectAsXml($value, &$parent, &$dom): array
     {
         $refl = new \ReflectionObject($value);
         foreach ($refl->getProperties() as $pr) {
@@ -147,6 +147,6 @@ private function _future_serializeObjectAsXml($value, &$parent, &$dom)
                 $this->_future_serializeAsXml($pr->getValue($value), $el, $dom);
             }
         }
-        return array($parent, $dom);
+        return [$parent, $dom];
     }
 }
\ No newline at end of file
diff --git a/src/Httpful/Http.php b/src/Httpful/Http.php
index 1c9aa0d..c56ab93 100644
--- a/src/Httpful/Http.php
+++ b/src/Httpful/Http.php
@@ -7,28 +7,28 @@
  */
 class Http
 {
-    const HEAD      = 'HEAD';
-    const GET       = 'GET';
-    const POST      = 'POST';
-    const PUT       = 'PUT';
-    const DELETE    = 'DELETE';
-    const PATCH     = 'PATCH';
-    const OPTIONS   = 'OPTIONS';
-    const TRACE     = 'TRACE';
+    public const HEAD      = 'HEAD';
+    public const GET       = 'GET';
+    public const POST      = 'POST';
+    public const PUT       = 'PUT';
+    public const DELETE    = 'DELETE';
+    public const PATCH     = 'PATCH';
+    public const OPTIONS   = 'OPTIONS';
+    public const TRACE     = 'TRACE';
 
     /**
      * @return array of HTTP method strings
      */
-    public static function safeMethods()
+    public static function safeMethods(): array
     {
-        return array(self::HEAD, self::GET, self::OPTIONS, self::TRACE);
+        return [self::HEAD, self::GET, self::OPTIONS, self::TRACE];
     }
 
     /**
      * @param string HTTP method
      * @return bool
      */
-    public static function isSafeMethod($method)
+    public static function isSafeMethod($method): bool
     {
         return in_array($method, self::safeMethods());
     }
@@ -37,7 +37,7 @@ public static function isSafeMethod($method)
      * @param string HTTP method
      * @return bool
      */
-    public static function isUnsafeMethod($method)
+    public static function isUnsafeMethod($method): bool
     {
         return !in_array($method, self::safeMethods());
     }
@@ -45,19 +45,19 @@ public static function isUnsafeMethod($method)
     /**
      * @return array list of (always) idempotent HTTP methods
      */
-    public static function idempotentMethods()
+    public static function idempotentMethods(): array
     {
         // Though it is possible to be idempotent, POST
         // is not guarunteed to be, and more often than
         // not, it is not.
-        return array(self::HEAD, self::GET, self::PUT, self::DELETE, self::OPTIONS, self::TRACE, self::PATCH);
+        return [self::HEAD, self::GET, self::PUT, self::DELETE, self::OPTIONS, self::TRACE, self::PATCH];
     }
 
     /**
      * @param string HTTP method
      * @return bool
      */
-    public static function isIdempotent($method)
+    public static function isIdempotent($method): bool
     {
         return in_array($method, self::safeidempotentMethodsMethods());
     }
@@ -66,7 +66,7 @@ public static function isIdempotent($method)
      * @param string HTTP method
      * @return bool
      */
-    public static function isNotIdempotent($method)
+    public static function isNotIdempotent($method): bool
     {
         return !in_array($method, self::idempotentMethods());
     }
@@ -78,9 +78,9 @@ public static function isNotIdempotent($method)
      *
      * @return array of HTTP method strings
      */
-    public static function canHaveBody()
+    public static function canHaveBody(): array
     {
-        return array(self::POST, self::PUT, self::PATCH, self::OPTIONS);
+        return [self::POST, self::PUT, self::PATCH, self::OPTIONS];
     }
 
 }
\ No newline at end of file
diff --git a/src/Httpful/Httpful.php b/src/Httpful/Httpful.php
index e235fa3..98d49b7 100644
--- a/src/Httpful/Httpful.php
+++ b/src/Httpful/Httpful.php
@@ -3,9 +3,9 @@
 namespace Httpful;
 
 class Httpful {
-    const VERSION = '0.3.0';
+    public const VERSION = '0.3.0';
 
-    private static $mimeRegistrar = array();
+    private static $mimeRegistrar = [];
     private static $default = null;
 
     /**
@@ -40,7 +40,7 @@ public static function get($mimeType = null)
      * @param string $mimeType
      * @return bool
      */
-    public static function hasParserRegistered($mimeType)
+    public static function hasParserRegistered($mimeType): bool
     {
         return isset(self::$mimeRegistrar[$mimeType]);
     }
diff --git a/src/Httpful/Mime.php b/src/Httpful/Mime.php
index 930b6e3..bd72396 100644
--- a/src/Httpful/Mime.php
+++ b/src/Httpful/Mime.php
@@ -8,35 +8,35 @@
  */
 class Mime
 {
-    const JSON    = 'application/json';
-    const XML     = 'application/xml';
-    const XHTML   = 'application/html+xml';
-    const FORM    = 'application/x-www-form-urlencoded';
-    const UPLOAD  = 'multipart/form-data';
-    const PLAIN   = 'text/plain';
-    const JS      = 'text/javascript';
-    const HTML    = 'text/html';
-    const YAML    = 'application/x-yaml';
-    const CSV     = 'text/csv';
+    public const JSON    = 'application/json';
+    public const XML     = 'application/xml';
+    public const XHTML   = 'application/html+xml';
+    public const FORM    = 'application/x-www-form-urlencoded';
+    public const UPLOAD  = 'multipart/form-data';
+    public const PLAIN   = 'text/plain';
+    public const JS      = 'text/javascript';
+    public const HTML    = 'text/html';
+    public const YAML    = 'application/x-yaml';
+    public const CSV     = 'text/csv';
 
     /**
      * Map short name for a mime type
      * to a full proper mime type
      */
-    public static $mimes = array(
+    public static $mimes = [
         'json'      => self::JSON,
         'xml'       => self::XML,
         'form'      => self::FORM,
         'plain'     => self::PLAIN,
         'text'      => self::PLAIN,
-        'upload'      => self::UPLOAD,
+        'upload'    => self::UPLOAD,
         'html'      => self::HTML,
         'xhtml'     => self::XHTML,
         'js'        => self::JS,
         'javascript'=> self::JS,
         'yaml'      => self::YAML,
         'csv'       => self::CSV,
-    );
+    ];
 
     /**
      * Get the full Mime Type name from a "short name".
@@ -44,16 +44,16 @@ class Mime
      * @param string $short_name common name for mime type (e.g. json)
      * @return string full mime type (e.g. application/json)
      */
-    public static function getFullMime($short_name)
-    {
-        return array_key_exists($short_name, self::$mimes) ? self::$mimes[$short_name] : $short_name;
+    public static function getFullMime(string $short_name): string
+    {        
+        return self::$mimes[$short_name] ?? $short_name;
     }
 
     /**
      * @param string $short_name
      * @return bool
      */
-    public static function supportsMimeType($short_name)
+    public static function supportsMimeType(string $short_name): bool
     {
         return array_key_exists($short_name, self::$mimes);
     }
diff --git a/src/Httpful/Proxy.php b/src/Httpful/Proxy.php
index 4ab9ea6..611f017 100644
--- a/src/Httpful/Proxy.php
+++ b/src/Httpful/Proxy.php
@@ -10,7 +10,7 @@
  */
 class Proxy
 {
-    const HTTP = CURLPROXY_HTTP;
-    const SOCKS4 = CURLPROXY_SOCKS4;
-    const SOCKS5 = CURLPROXY_SOCKS5;
+    public const HTTP = CURLPROXY_HTTP;
+    public const SOCKS4 = CURLPROXY_SOCKS4;
+    public const SOCKS5 = CURLPROXY_SOCKS5;
 }
diff --git a/src/Httpful/Request.php b/src/Httpful/Request.php
index c04d230..e7b91c8 100644
--- a/src/Httpful/Request.php
+++ b/src/Httpful/Request.php
@@ -1,5 +1,4 @@
 <?php
-
 namespace Httpful;
 
 use Httpful\Exception\ConnectionErrorException;
@@ -47,20 +46,20 @@ class Request
 {
 
     // Option constants
-    const SERIALIZE_PAYLOAD_NEVER   = 0;
-    const SERIALIZE_PAYLOAD_ALWAYS  = 1;
-    const SERIALIZE_PAYLOAD_SMART   = 2;
+    public const SERIALIZE_PAYLOAD_NEVER   = 0;
+    public const SERIALIZE_PAYLOAD_ALWAYS  = 1;
+    public const SERIALIZE_PAYLOAD_SMART   = 2;
 
-    const MAX_REDIRECTS_DEFAULT     = 25;
+    public const MAX_REDIRECTS_DEFAULT     = 25;
 
     public $uri,
            $method                  = Http::GET,
-           $headers                 = array(),
+           $headers                 = [],
            $raw_headers             = '',
            $strict_ssl              = false,
            $content_type,
            $expected_type,
-           $additional_curl_opts    = array(),
+           $additional_curl_opts    = [],
            $auto_parse              = true,
            $serialize_payload_method = self::SERIALIZE_PAYLOAD_SMART,
            $username,
@@ -72,7 +71,12 @@ class Request
            $send_callback,
            $follow_redirects        = false,
            $max_redirects           = self::MAX_REDIRECTS_DEFAULT,
-           $payload_serializers     = array();
+           $payload_serializers     = [],
+           $timeout                 = null,
+           $client_cert             = null,
+           $client_key              = null,
+           $client_passphrase       = null,
+           $client_encoding         = null;
 
     // Options
     // private $_options = array(
@@ -98,7 +102,8 @@ protected function __construct($attrs = null)
     {
         if (!is_array($attrs)) return;
         foreach ($attrs as $attr => $value) {
-            $this->$attr = $value;
+            if (property_exists($this, $attr))
+                $this->$attr = $value;
         }
     }
 
@@ -146,33 +151,33 @@ public static function d($attr)
     /**
      * @return bool does the request have a timeout?
      */
-    public function hasTimeout()
+    public function hasTimeout(): bool
     {
-        return isset($this->timeout);
+        return $this->timeout !== null;
     }
 
     /**
      * @return bool has the internal curl request been initialized?
      */
-    public function hasBeenInitialized()
+    public function hasBeenInitialized(): bool
     {
-        return isset($this->_ch);
+        return $this->_ch !== null;
     }
 
     /**
      * @return bool Is this request setup for basic auth?
      */
-    public function hasBasicAuth()
+    public function hasBasicAuth(): bool
     {
-        return isset($this->password) && isset($this->username);
+        return $this->password !== null && $this->username !== null;
     }
 
     /**
      * @return bool Is this request setup for digest auth?
      */
-    public function hasDigestAuth()
+    public function hasDigestAuth(): bool
     {
-        return isset($this->password) && isset($this->username) && $this->additional_curl_opts[CURLOPT_HTTPAUTH] == CURLAUTH_DIGEST;
+        return $this->password !== null && $this->username !== null && $this->additional_curl_opts[CURLOPT_HTTPAUTH] == CURLAUTH_DIGEST;
     }
 
     /**
@@ -307,9 +312,9 @@ public function authenticateWithDigest($username, $password)
     /**
      * @return bool is this request setup for client side cert?
      */
-    public function hasClientSideCert()
+    public function hasClientSideCert(): bool
     {
-        return isset($this->client_cert) && isset($this->client_key);
+        return $this->client_cert !== null && $this->client_key !==null;
     }
 
     /**
@@ -395,14 +400,15 @@ public function method($method)
      * @param string $mime
      * @return Request
      */
-    public function expects($mime)
+    public function expects(?string $mime)
     {
         if (empty($mime)) return $this;
         $this->expected_type = Mime::getFullMime($mime);
+
         return $this;
     }
     // @alias of expects
-    public function expectsType($mime)
+    public function expectsType(?string $mime)
     {
         return $this->expects($mime);
     }
@@ -481,7 +487,7 @@ public function useProxy($proxy_host, $proxy_port = 80, $auth_type = null, $auth
     {
         $this->addOnCurlOption(CURLOPT_PROXY, "{$proxy_host}:{$proxy_port}");
         $this->addOnCurlOption(CURLOPT_PROXYTYPE, $proxy_type);
-        if (in_array($auth_type, array(CURLAUTH_BASIC,CURLAUTH_NTLM))) {
+        if (in_array($auth_type, [CURLAUTH_BASIC,CURLAUTH_NTLM])) {
             $this->addOnCurlOption(CURLOPT_PROXYAUTH, $auth_type)
                 ->addOnCurlOption(CURLOPT_PROXYUSERPWD, "{$auth_username}:{$auth_password}");
         }
@@ -511,7 +517,7 @@ public function useSocks5Proxy($proxy_host, $proxy_port = 80, $auth_type = null,
     /**
      * @return bool is this request setup for using proxy?
      */
-    public function hasProxy()
+    public function hasProxy(): bool
     {
         /* We must be aware that proxy variables could come from environment also.
            In curl extension, http proxy can be specified not only via CURLOPT_PROXY option, 
@@ -743,6 +749,7 @@ public function __call($method, $args)
             //     throw new \Exception("Unsupported Content-Type $mime");
             // }
         }
+
         if (substr($method, 0, 7) === 'expects') {
             $mime = strtolower(substr($method, 7));
             if (Mime::supportsMimeType($mime)) {
@@ -756,7 +763,7 @@ public function __call($method, $args)
 
         // This method also adds the custom header support as described in the
         // method comments
-        if (count($args) === 0)
+        if ($args === [])
             return;
 
         // Strip the sugar.  If it leads with "with", strip.
@@ -791,7 +798,7 @@ private static function _initializeDefaults()
         // recusion.  Do not use this syntax elsewhere.
         // It goes against the whole readability
         // and transparency idea.
-        self::$_template = new Request(array('method' => Http::GET));
+        self::$_template = new Request(['method' => Http::GET]);
 
         // This is more like it...
         self::$_template
@@ -818,7 +825,7 @@ private function _error($error)
     {
         // TODO add in support for various Loggers that follow
         // PSR 3 https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-3-logger-interface.md
-        if (isset($this->error_callback)) {
+        if ($this->error_callback !== null) {
             $this->error_callback->__invoke($error);
         } else {
             error_log($error);
@@ -860,14 +867,14 @@ public static function init($method = null, $mime = null)
     public function _curlPrep()
     {
         // Check for required stuff
-        if (!isset($this->uri))
+        if ($this->uri === null)
             throw new \Exception('Attempting to send a request before defining a URI endpoint.');
 
-        if (isset($this->payload)) {
+        if ($this->payload !== null) {
             $this->serialized_payload = $this->_serializePayload($this->payload);
         }
 
-        if (isset($this->send_callback)) {
+        if ($this->send_callback !== null) {
             call_user_func($this->send_callback, $this);
         }
 
@@ -921,7 +928,7 @@ public function _curlPrep()
 
         // https://github.com/nategood/httpful/issues/84
         // set Content-Length to the size of the payload if present
-        if (isset($this->payload)) {
+        if ($this->payload !== null) {
             curl_setopt($ch, CURLOPT_POSTFIELDS, $this->serialized_payload);
             if (!$this->isUpload()) {
                 $this->headers['Content-Length'] =
@@ -929,7 +936,7 @@ public function _curlPrep()
             }
         }
 
-        $headers = array();
+        $headers = [];
         // https://github.com/nategood/httpful/issues/37
         // Except header removes any HTTP 1.1 Continue from response headers
         $headers[] = 'Expect:';
@@ -962,9 +969,9 @@ public function _curlPrep()
         }
 
         $url = \parse_url($this->uri);
-        $path = (isset($url['path']) ? $url['path'] : '/').(isset($url['query']) ? '?'.$url['query'] : '');
+        $path = ($url['path'] ?? '/').(isset($url['query']) ? '?'.$url['query'] : '');
         $this->raw_headers = "{$this->method} $path HTTP/1.1\r\n";
-        $host = (isset($url['host']) ? $url['host'] : 'localhost').(isset($url['port']) ? ':'.$url['port'] : '');
+        $host = ($url['host'] ?? 'localhost').(isset($url['port']) ? ':'.$url['port'] : '');
         $this->raw_headers .= "Host: $host\r\n";
         $this->raw_headers .= \implode("\r\n", $headers);
         $this->raw_headers .= "\r\n";
@@ -1004,7 +1011,7 @@ public function _determineLength($str)
     /**
      * @return bool
      */
-    public function isUpload()
+    public function isUpload(): bool
     {
         return Mime::UPLOAD == $this->content_type;
     }
@@ -1012,7 +1019,7 @@ public function isUpload()
     /**
      * @return string
      */
-    public function buildUserAgent()
+    public function buildUserAgent(): string
     {
         $user_agent = 'User-Agent: Httpful/' . Httpful::VERSION . ' (cURL/';
         $curl = \curl_version();
@@ -1042,9 +1049,7 @@ public function buildUserAgent()
             $user_agent .= " {$_SERVER['HTTP_USER_AGENT']}";
         }
 
-        $user_agent .= ')';
-
-        return $user_agent;
+        return $user_agent . ')';
     }
 
     /**
@@ -1053,7 +1058,7 @@ public function buildUserAgent()
      */
     public function buildResponse($result) {
         if ($result === false) {
-            if ($curlErrorNumber = curl_errno($this->_ch)) {
+            if (($curlErrorNumber = curl_errno($this->_ch)) !== 0) {
                 $curlErrorString = curl_error($this->_ch);
                 $this->_error($curlErrorString);
 
@@ -1082,7 +1087,7 @@ public function buildResponse($result) {
 
         $body = array_pop($response);
         $headers = array_pop($response);
-
+        
         return new Response($body, $headers, $this, $info);
     }
 
diff --git a/src/Httpful/Response.php b/src/Httpful/Response.php
index 09996b6..2e1d204 100644
--- a/src/Httpful/Response.php
+++ b/src/Httpful/Response.php
@@ -9,7 +9,6 @@
  */
 class Response
 {
-
     public $body,
            $raw_body,
            $headers,
@@ -18,7 +17,7 @@ class Response
            $code = 0,
            $content_type,
            $parent_type,
-           $charset,
+           $charset             = null,
            $meta_data,
            $is_mime_vendor_specific = false,
            $is_mime_personal = false;
@@ -31,7 +30,7 @@ class Response
      * @param Request $request
      * @param array $meta_data
      */
-    public function __construct($body, $headers, Request $request, array $meta_data = array())
+    public function __construct(string $body, string $headers, Request $request, array $meta_data = [])
     {
         $this->request      = $request;
         $this->raw_headers  = $headers;
@@ -59,7 +58,7 @@ public function __construct($body, $headers, Request $request, array $meta_data
      *
      * @return bool Did we receive a 4xx or 5xx?
      */
-    public function hasErrors()
+    public function hasErrors(): bool
     {
         return $this->code >= 400;
     }
@@ -67,7 +66,7 @@ public function hasErrors()
     /**
      * @return bool
      */
-    public function hasBody()
+    public function hasBody(): bool
     {
         return !empty($this->body);
     }
@@ -77,9 +76,9 @@ public function hasBody()
      * (most often an associative array) based on the expected
      * Mime type.
      * @param string Http response body
-     * @return array|string|object the response parse accordingly
+     * @return mixed (array|string|object) the response parse accordingly
      */
-    public function _parse($body)
+    public function _parse(string $body)
     {
         // If the user decided to forgo the automatic
         // smart parsing, short circuit.
@@ -98,13 +97,13 @@ public function _parse($body)
         //  3. If provided, use the "parent type" of the mime type from the response
         //  4. Default to the content-type provided in the response
         $parse_with = $this->request->expected_type;
+
         if (empty($this->request->expected_type)) {
             $parse_with = Httpful::hasParserRegistered($this->content_type)
                 ? $this->content_type
                 : $this->parent_type;
         }
-
-       return Httpful::get($parse_with)->parse($body);
+        return Httpful::get($parse_with)->parse($body);
     }
 
     /**
@@ -113,12 +112,12 @@ public function _parse($body)
      * @param string $headers raw headers
      * @return array parse headers
      */
-    public function _parseHeaders($headers)
+    public function _parseHeaders(string $headers): array
     {
         return Response\Headers::fromString($headers)->toArray();
     }
 
-    public function _parseCode($headers)
+    public function _parseCode(string $headers): int
     {
         $end = strpos($headers, "\r\n");
         if ($end === false) $end = strlen($headers);
@@ -126,7 +125,7 @@ public function _parseCode($headers)
         if (count($parts) < 2 || !is_numeric($parts[1])) {
             throw new \Exception("Unable to parse response code from HTTP response due to malformed response");
         }
-        return intval($parts[1]);
+        return (int) $parts[1];
     }
 
     /**
@@ -136,12 +135,12 @@ public function _parseCode($headers)
     public function _interpretHeaders()
     {
         // Parse the Content-Type and charset
-        $content_type = isset($this->headers['Content-Type']) ? $this->headers['Content-Type'] : '';
+        $content_type = $this->headers['Content-Type'] ?? '';
         $content_type = explode(';', $content_type);
 
         $this->content_type = $content_type[0];
         if (count($content_type) == 2 && strpos($content_type[1], '=') !== false) {
-            list($nill, $this->charset) = explode('=', $content_type[1]);
+            [$nill, $this->charset] = explode('=', $content_type[1]);
         }
 
         // RFC 2616 states "text/*" Content-Types should have a default
@@ -149,13 +148,13 @@ public function _interpretHeaders()
         // are assumed to have UTF-8 unless otherwise specified.
         // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
         // http://www.w3.org/International/O-HTTP-charset.en.php
-        if (!isset($this->charset)) {
+        if ($this->charset === null ) {
             $this->charset = substr($this->content_type, 5) === 'text/' ? 'iso-8859-1' : 'utf-8';
         }
 
         // Is vendor type? Is personal type?
         if (strpos($this->content_type, '/') !== false) {
-            list($type, $sub_type) = explode('/', $this->content_type);
+            [$type, $sub_type] = explode('/', $this->content_type);
             $this->is_mime_vendor_specific = substr($sub_type, 0, 4) === 'vnd.';
             $this->is_mime_personal = substr($sub_type, 0, 4) === 'prs.';
         }
@@ -163,7 +162,7 @@ public function _interpretHeaders()
         // Parent type (e.g. xml for application/vnd.github.message+xml)
         $this->parent_type = $this->content_type;
         if (strpos($this->content_type, '+') !== false) {
-            list($vendor, $this->parent_type) = explode('+', $this->content_type, 2);
+            [$vendor, $this->parent_type] = explode('+', $this->content_type, 2);
             $this->parent_type = Mime::getFullMime($this->parent_type);
         }
     }
@@ -171,7 +170,7 @@ public function _interpretHeaders()
     /**
      * @return string
      */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->raw_body;
     }
diff --git a/src/Httpful/Response/Headers.php b/src/Httpful/Response/Headers.php
index 8e8a8cd..32438b7 100644
--- a/src/Httpful/Response/Headers.php
+++ b/src/Httpful/Response/Headers.php
@@ -15,15 +15,16 @@ private function __construct($headers)
     }
 
     /**
-     * @param string $string
+     * @param string $string 
      * @return Headers
      */
     public static function fromString($string)
     {
         $headers = preg_split("/(\r|\n)+/", $string, -1, \PREG_SPLIT_NO_EMPTY);
-        $parse_headers = array();
-        for ($i = 1; $i < count($headers); $i++) {
-            list($key, $raw_value) = explode(':', $headers[$i], 2);
+        $parse_headers = [];
+        $headersCount = count($headers);
+        for ($i = 1; $i < $headersCount; $i++) {
+            [$key, $raw_value] = explode(':', $headers[$i], 2);
             $key = trim($key);
             $value = trim($raw_value);
             if (array_key_exists($key, $parse_headers)) {
@@ -42,17 +43,17 @@ public static function fromString($string)
 
     /**
      * @param string $offset
-     * @return bool
      */
-    public function offsetExists($offset)
+    public function offsetExists($offset): bool
     {
         return $this->getCaseInsensitive($offset) !== null;
     }
 
     /**
-     * @param string $offset
+     * @param mixed $offset
      * @return mixed
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($offset)
     {
         return $this->getCaseInsensitive($offset);
@@ -62,7 +63,9 @@ public function offsetGet($offset)
      * @param string $offset
      * @param string $value
      * @throws \Exception
+     * @return never
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
     {
         throw new \Exception("Headers are read-only.");
@@ -71,7 +74,9 @@ public function offsetSet($offset, $value)
     /**
      * @param string $offset
      * @throws \Exception
+     * @return never
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
     {
         throw new \Exception("Headers are read-only.");
@@ -80,7 +85,7 @@ public function offsetUnset($offset)
     /**
      * @return int
      */
-    public function count()
+    public function count(): int
     {
         return count($this->headers);
     }
diff --git a/tests/Httpful/HttpfulTest.php b/tests/Httpful/HttpfulTest.php
index 062973e..3b8787f 100644
--- a/tests/Httpful/HttpfulTest.php
+++ b/tests/Httpful/HttpfulTest.php
@@ -9,7 +9,7 @@
  */
 namespace Httpful\Test;
 
-require(dirname(dirname(dirname(__FILE__))) . '/bootstrap.php');
+require(dirname(__FILE__),3) . '/bootstrap.php');
 \Httpful\Bootstrap::init();
 
 use Httpful\Httpful;
@@ -23,16 +23,16 @@
 
 class HttpfulTest extends \PHPUnit\Framework\TestCase
 {
-    const TEST_SERVER = TEST_SERVER;
-    const TEST_URL = 'http://127.0.0.1:8008';
-    const TEST_URL_400 = 'http://127.0.0.1:8008/400';
+    public const TEST_SERVER = TEST_SERVER;
+    public const TEST_URL = 'http://127.0.0.1:8008';
+    public const TEST_URL_400 = 'http://127.0.0.1:8008/400';
 
-    const SAMPLE_JSON_HEADER =
+    public const SAMPLE_JSON_HEADER =
 "HTTP/1.1 200 OK
 Content-Type: application/json
 Connection: keep-alive
 Transfer-Encoding: chunked\r\n";
-    const SAMPLE_JSON_HEADER_LOWERCASE =
+    public const SAMPLE_JSON_HEADER_LOWERCASE =
         "HTTP/2 200 
 date: Tue, 07 Jan 2020 09:11:21 GMT
 content-type: application/json
@@ -41,29 +41,29 @@ class HttpfulTest extends \PHPUnit\Framework\TestCase
 access-control-allow-methods: GET, POST, PUT, PATCH, DELETE
 access-control-allow-headers: Authorization, Content-Type, Accept-Encoding, Cache-Control, DNT
 cache-control: private, must-revalidate\r\n";
-    const SAMPLE_JSON_RESPONSE = '{"key":"value","object":{"key":"value"},"array":[1,2,3,4]}';
-    const SAMPLE_CSV_HEADER =
+    public const SAMPLE_JSON_RESPONSE = '{"key":"value","object":{"key":"value"},"array":[1,2,3,4]}';
+    public const SAMPLE_CSV_HEADER =
 "HTTP/1.1 200 OK
 Content-Type: text/csv
 Connection: keep-alive
 Transfer-Encoding: chunked\r\n";
-    const SAMPLE_CSV_RESPONSE =
+    public const SAMPLE_CSV_RESPONSE =
 "Key1,Key2
 Value1,Value2
 \"40.0\",\"Forty\"";
-    const SAMPLE_XML_RESPONSE = '<stdClass><arrayProp><array><k1><myClass><intProp>2</intProp></myClass></k1></array></arrayProp><stringProp>a string</stringProp><boolProp>TRUE</boolProp></stdClass>';
-    const SAMPLE_XML_HEADER =
+    public const SAMPLE_XML_RESPONSE = '<stdClass><arrayProp><array><k1><myClass><intProp>2</intProp></myClass></k1></array></arrayProp><stringProp>a string</stringProp><boolProp>TRUE</boolProp></stdClass>';
+    public const SAMPLE_XML_HEADER =
 "HTTP/1.1 200 OK
 Content-Type: application/xml
 Connection: keep-alive
 Transfer-Encoding: chunked\r\n";
-    const SAMPLE_VENDOR_HEADER =
+    public const SAMPLE_VENDOR_HEADER =
 "HTTP/1.1 200 OK
 Content-Type: application/vnd.nategood.message+xml
 Connection: keep-alive
 Transfer-Encoding: chunked\r\n";
-    const SAMPLE_VENDOR_TYPE = "application/vnd.nategood.message+xml";
-    const SAMPLE_MULTI_HEADER =
+    public const SAMPLE_VENDOR_TYPE = "application/vnd.nategood.message+xml";
+    public const SAMPLE_MULTI_HEADER =
 "HTTP/1.1 200 OK
 Content-Type: application/json
 Connection: keep-alive
@@ -74,8 +74,8 @@ class HttpfulTest extends \PHPUnit\Framework\TestCase
     function testInit()
     {
       $r = Request::init();
-      // Did we get a 'Request' object?
-      $this->assertEquals('Httpful\Request', get_class($r));
+      // Did we get a 'Request' object?      
+      $this->assertEquals(\Httpful\Request::class, get_class($r));
     }
 
     function testDetermineLength()
@@ -90,11 +90,11 @@ function testDetermineLength()
 
     function testMethods()
     {
-      $valid_methods = array('get', 'post', 'delete', 'put', 'options', 'head');
+      $valid_methods = ['get', 'post', 'delete', 'put', 'options', 'head'];
       $url = 'http://example.com/';
-      foreach ($valid_methods as $method) {
-        $r = call_user_func(array('Httpful\Request', $method), $url);
-        $this->assertEquals('Httpful\Request', get_class($r));
+      foreach ($valid_methods as $method) {        
+        $r = call_user_func([\Httpful\Request::class, $method], $url);
+        $this->assertEquals(\Httpful\Request::class, get_class($r));        
         $this->assertEquals(strtoupper($method), $r->method);
       }
     }
@@ -344,10 +344,10 @@ function testParsingContentTypeUpload()
     }
 
     function testAttach() {
-        $req = Request::init();
-        $testsPath = realpath(dirname(__FILE__) . DIRECTORY_SEPARATOR . '..');
-        $filename = $testsPath . DIRECTORY_SEPARATOR . 'test_image.jpg';
-        $req->attach(array('index' => $filename));
+        $req = Request::init();        
+        $testsPath = realpath(__DIR__ . DIRECTORY_SEPARATOR . '..');
+        $filename = $testsPath . DIRECTORY_SEPARATOR . 'test_image.jpg';        
+        $req->attach(['index' => $filename]);
         $payload = $req->payload['index'];
         // PHP 5.5  + will take advantage of CURLFile while previous
         // versions just use the string syntax
@@ -558,7 +558,7 @@ public function testOverrideXmlHandler()
         // Lazy test...
         $prev = \Httpful\Httpful::get(\Httpful\Mime::XML);
         $this->assertEquals($prev, new \Httpful\Handlers\XmlHandler());
-        $conf = array('namespace' => 'http://example.com');
+        $conf = ['namespace' => 'http://example.com'];
         \Httpful\Httpful::register(\Httpful\Mime::XML, new \Httpful\Handlers\XmlHandler($conf));
         $new = \Httpful\Httpful::get(\Httpful\Mime::XML);
         $this->assertNotEquals($prev, $new);
@@ -589,12 +589,12 @@ public function testParseJSON()
     {
         $handler = new JsonHandler();
 
-        $bodies = array(
+        $bodies = [
             'foo',
-            array(),
-            array('foo', 'bar'),
+            [],
+            ['foo', 'bar'],
             null
-        );
+        ];
         foreach ($bodies as $body) {
             $this->assertEquals($body, $handler->parse(json_encode($body)));
         }
diff --git a/tests/bootstrap-server.php b/tests/bootstrap-server.php
index 1c27bd9..1ac0dad 100644
--- a/tests/bootstrap-server.php
+++ b/tests/bootstrap-server.php
@@ -1,7 +1,7 @@
 <?php
 
 $php_version = phpversion();
-$php_major = floatval(substr($php_version, 0, 3));
+$php_major = (float) substr($php_version, 0, 3);
 
 // Define SIGKILL if pcntl is not found
 if (!function_exists('pcntl_signal')) {
@@ -15,7 +15,7 @@
     $command = sprintf('php -S %s:%d -t %s >./server.log 2>&1 & echo $!', WEB_SERVER_HOST, WEB_SERVER_PORT, WEB_SERVER_DOCROOT);
 
     // Execute the command and store the process ID
-    $output = array();
+    $output = [];
     exec($command, $output, $exit_code);
 
     // sleep for a second to let server come up