diff --git a/Makefile b/Makefile
index 241534d..a8976fb 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,9 @@ vendor: composer.phar
 composer.phar:
 	@curl -sS https://getcomposer.org/installer | php
 
+docker:
+	@docker run -it --rm -v ${PWD}:/app -w /app chialab/php:7.4 bash
+
 test: lint
 	@vendor/bin/phpunit --colors test/
 	@php ./composer.phar validate
@@ -23,7 +26,7 @@ lint: dependencies
 
 release:
 	@printf "releasing ${VERSION}..."
-	@printf '<?php\nglobal $$POSTHOG_VERSION;\n$$POSTHOG_VERSION = "%b";\n' ${VERSION} > ./lib/PostHog/Version.php
+	@sed -Ei "s/(public const VERSION =).+/\1 '${VERSION}';/" ./lib/PostHog.php
 	@node -e "var fs = require('fs'), pkg = require('./composer'); pkg.version = '${VERSION}'; fs.writeFileSync('./composer.json', JSON.stringify(pkg, null, '\t'));"
 	@git changelog -t ${VERSION}
 	@git release ${VERSION}
diff --git a/bin/posthog b/bin/posthog
index d2b6224..775cc79 100755
--- a/bin/posthog
+++ b/bin/posthog
@@ -1,7 +1,9 @@
 #!/usr/bin/env php
 <?php
 
-require_once(__DIR__ . '/../lib/PostHog.php');
+require_once __DIR__ . '/../vendor/autoload.php';
+
+use PostHog\PostHog;
 
 if (in_array('--help', $argv)) {
   print(usage());
diff --git a/composer.json b/composer.json
index db06ad9..7b7a433 100644
--- a/composer.json
+++ b/composer.json
@@ -18,13 +18,13 @@
 	},
 	"require-dev": {
 		"phpunit/phpunit": "~8.0",
-		"overtrue/phplint": "^1.2",
+		"overtrue/phplint": "^2.3",
 		"squizlabs/php_codesniffer": "^3.5"
 	},
 	"autoload": {
-		"files": [
-			"lib/PostHog.php"
-		]
+		"psr-4": {
+			"PostHog\\": "lib/"
+		}
 	},
 	"bin": [
 		"bin/posthog"
diff --git a/lib/PostHog/Client.php b/lib/Client.php
similarity index 87%
rename from lib/PostHog/Client.php
rename to lib/Client.php
index 4b67fe2..e2d91fd 100644
--- a/lib/PostHog/Client.php
+++ b/lib/Client.php
@@ -1,14 +1,13 @@
 <?php
 
-require_once(__DIR__ . '/Consumer.php');
-require_once(__DIR__ . '/QueueConsumer.php');
-require_once(__DIR__ . '/Consumer/File.php');
-require_once(__DIR__ . '/Consumer/ForkCurl.php');
-require_once(__DIR__ . '/Consumer/LibCurl.php');
-require_once(__DIR__ . '/Consumer/Socket.php');
-require_once(__DIR__ . '/Version.php');
+namespace PostHog;
 
-class PostHog_Client {
+use PostHog\Consumer\File;
+use PostHog\Consumer\ForkCurl;
+use PostHog\Consumer\LibCurl;
+use PostHog\Consumer\Socket;
+
+class Client {
 
   /**
    * Consumer object handles queueing and bundling requests to Posthog.
@@ -28,10 +27,10 @@ class PostHog_Client {
    */
   public function __construct($apiKey, $options = array()) {
     $consumers = array(
-      "socket"     => "PostHog_Consumer_Socket",
-      "file"       => "PostHog_Consumer_File",
-      "fork_curl"  => "PostHog_Consumer_ForkCurl",
-      "lib_curl"   => "PostHog_Consumer_LibCurl"
+      "socket"     => Socket::class,
+      "file"       => File::class,
+      "fork_curl"  => ForkCurl::class,
+      "lib_curl"   => LibCurl::class,
     );
 
     // Use our socket libcurl by default
@@ -174,18 +173,16 @@ private function formatTime($ts) {
    */
 
   private function message($msg){
-    global $POSTHOG_VERSION;
-
     if (!isset($msg["properties"])) {
       $msg["properties"] = array();
     }
 
     $msg["library"] = 'posthog-php';
-    $msg["library_version"] = $POSTHOG_VERSION;
+    $msg["library_version"] = PostHog::VERSION;
     $msg["library_consumer"] = $this->consumer->getConsumer();
 
     $msg["properties"]['$lib'] = 'posthog-php';
-    $msg["properties"]['$lib_version'] = $POSTHOG_VERSION;
+    $msg["properties"]['$lib_version'] = PostHog::VERSION;
     $msg["properties"]['$lib_consumer'] = $this->consumer->getConsumer();
 
     if (isset($msg["distinctId"])) {
diff --git a/lib/PostHog/Consumer.php b/lib/Consumer.php
similarity index 97%
rename from lib/PostHog/Consumer.php
rename to lib/Consumer.php
index c660954..32d5bd1 100644
--- a/lib/PostHog/Consumer.php
+++ b/lib/Consumer.php
@@ -1,5 +1,8 @@
 <?php
-abstract class PostHog_Consumer {
+
+namespace PostHog;
+
+abstract class Consumer {
   protected $type = "Consumer";
 
   protected $options;
diff --git a/lib/PostHog/Consumer/File.php b/lib/Consumer/File.php
similarity index 94%
rename from lib/PostHog/Consumer/File.php
rename to lib/Consumer/File.php
index d283b31..94e42da 100644
--- a/lib/PostHog/Consumer/File.php
+++ b/lib/Consumer/File.php
@@ -1,6 +1,10 @@
 <?php
 
-class PostHog_Consumer_File extends PostHog_Consumer {
+namespace PostHog\Consumer;
+
+use PostHog\Consumer;
+
+class File extends Consumer {
   protected $type = "File";
 
   private $file_handle;
@@ -20,7 +24,7 @@ public function __construct($apiKey, $options = array()) {
     try {
       $this->file_handle = fopen($options["filename"], "a");
       chmod($options["filename"], 0777);
-    } catch (Exception $e) {
+    } catch (\Exception $e) {
       $this->handleError($e->getCode(), $e->getMessage());
     }
   }
diff --git a/lib/PostHog/Consumer/ForkCurl.php b/lib/Consumer/ForkCurl.php
similarity index 96%
rename from lib/PostHog/Consumer/ForkCurl.php
rename to lib/Consumer/ForkCurl.php
index eafd427..2f455e2 100644
--- a/lib/PostHog/Consumer/ForkCurl.php
+++ b/lib/Consumer/ForkCurl.php
@@ -1,6 +1,10 @@
 <?php
 
-class PostHog_Consumer_ForkCurl extends PostHog_QueueConsumer {
+namespace PostHog\Consumer;
+
+use PostHog\QueueConsumer;
+
+class ForkCurl extends QueueConsumer {
   protected $type = "ForkCurl";
 
   /**
diff --git a/lib/PostHog/Consumer/LibCurl.php b/lib/Consumer/LibCurl.php
similarity index 97%
rename from lib/PostHog/Consumer/LibCurl.php
rename to lib/Consumer/LibCurl.php
index ab384da..3796bea 100644
--- a/lib/PostHog/Consumer/LibCurl.php
+++ b/lib/Consumer/LibCurl.php
@@ -1,6 +1,10 @@
 <?php
 
-class PostHog_Consumer_LibCurl extends PostHog_QueueConsumer {
+namespace PostHog\Consumer;
+
+use PostHog\QueueConsumer;
+
+class LibCurl extends QueueConsumer {
   protected $type = "LibCurl";
 
   /**
diff --git a/lib/PostHog/Consumer/Socket.php b/lib/Consumer/Socket.php
similarity index 97%
rename from lib/PostHog/Consumer/Socket.php
rename to lib/Consumer/Socket.php
index 9625808..bf3404f 100644
--- a/lib/PostHog/Consumer/Socket.php
+++ b/lib/Consumer/Socket.php
@@ -1,6 +1,10 @@
 <?php
 
-class PostHog_Consumer_Socket extends PostHog_QueueConsumer {
+namespace PostHog\Consumer;
+
+use PostHog\QueueConsumer;
+
+class Socket extends QueueConsumer {
   protected $type = "Socket";
   private $socket_failed;
 
@@ -77,7 +81,7 @@ private function createSocket() {
       }
 
       return $socket;
-    } catch (Exception $e) {
+    } catch (\Exception $e) {
       $this->handleError($e->getCode(), $e->getMessage());
       $this->socket_failed = true;
 
@@ -107,7 +111,7 @@ private function makeRequest($socket, $req, $retry = true) {
         try {
           // Since we're try catch'ing prevent PHP logs.
           $written = @fwrite($socket, substr($req, $bytes_written));
-        } catch (Exception $e) {
+        } catch (\Exception $e) {
           $this->handleError($e->getCode(), $e->getMessage());
           $closed = true;
         }
diff --git a/lib/PostHog.php b/lib/PostHog.php
index da22ab4..0eceb6a 100644
--- a/lib/PostHog.php
+++ b/lib/PostHog.php
@@ -1,8 +1,12 @@
 <?php
 
-require_once __DIR__ . '/PostHog/Client.php';
+namespace PostHog;
+
+use PostHog\Client;
 
 class PostHog {
+  public const VERSION = '1.0.0';
+
   private static $client;
 
   /**
@@ -12,7 +16,7 @@ class PostHog {
    */
   public static function init($apiKey, $options = array()) {
     self::assert($apiKey, "PostHog::init() requires an apiKey");
-    self::$client = new PostHog_Client($apiKey, $options);
+    self::$client = new Client($apiKey, $options);
   }
 
   /**
diff --git a/lib/PostHog/Version.php b/lib/PostHog/Version.php
deleted file mode 100644
index 332a8b1..0000000
--- a/lib/PostHog/Version.php
+++ /dev/null
@@ -1,3 +0,0 @@
-<?php
-global $POSTHOG_VERSION;
-$POSTHOG_VERSION = "";
diff --git a/lib/PostHog/QueueConsumer.php b/lib/QueueConsumer.php
similarity index 97%
rename from lib/PostHog/QueueConsumer.php
rename to lib/QueueConsumer.php
index 1eb0d9f..8f43d2e 100644
--- a/lib/PostHog/QueueConsumer.php
+++ b/lib/QueueConsumer.php
@@ -1,6 +1,8 @@
 <?php
 
-abstract class PostHog_QueueConsumer extends PostHog_Consumer {
+namespace PostHog;
+
+abstract class QueueConsumer extends Consumer {
   protected $type = "QueueConsumer";
 
   protected $queue;
diff --git a/send.php b/send.php
index 9a345fe..b71e932 100755
--- a/send.php
+++ b/send.php
@@ -1,10 +1,12 @@
 <?php
 
+require_once __DIR__ . '/vendor/autoload.php';
+
 /**
  * require client
  */
 
-require_once(__DIR__ . "/lib/PostHog.php");
+use PostHog\PostHog;
 
 /**
  * Args
@@ -70,7 +72,7 @@
   if (!trim($line)) continue;
   $payload = json_decode($line, true);
   $type = $payload["type"];
-  $ret = call_user_func_array(array("PostHog", "raw"), array($payload));
+  $ret = call_user_func_array(array("PostHog\\PostHog", "raw"), array($payload));
   if ($ret) $successful++;
   $total++;
   if ($total % 100 === 0) PostHog::flush();
diff --git a/test/ConsumerFileTest.php b/test/ConsumerFileTest.php
index 71ec521..5b6a749 100644
--- a/test/ConsumerFileTest.php
+++ b/test/ConsumerFileTest.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once __DIR__ . "/../lib/PostHog/Client.php";
+use PostHog\Client;
 
 class ConsumerFileTest extends PHPUnit\Framework\TestCase
 {
@@ -14,7 +14,7 @@ public function setUp(): void
       unlink($this->filename());
     }
 
-    $this->client = new PostHog_Client(
+    $this->client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "consumer" => "file",
@@ -78,11 +78,11 @@ public function testSend()
   public function testProductionProblems()
   {
     // Open to a place where we should not have write access.
-    $client = new PostHog_Client(
+    $client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "consumer" => "file",
-        "filename" => "/dev/xxxxxxx",
+        "filename" => "/dev/x/xxxxxxx",
       )
     );
 
diff --git a/test/ConsumerForkCurlTest.php b/test/ConsumerForkCurlTest.php
index 764c0d6..4f5fff7 100644
--- a/test/ConsumerForkCurlTest.php
+++ b/test/ConsumerForkCurlTest.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once __DIR__ . "/../lib/PostHog/Client.php";
+use PostHog\Client;
 
 class ConsumerForkCurlTest extends PHPUnit\Framework\TestCase
 {
@@ -9,7 +9,7 @@ class ConsumerForkCurlTest extends PHPUnit\Framework\TestCase
   public function setUp(): void
   {
     date_default_timezone_set("UTC");
-    $this->client = new PostHog_Client(
+    $this->client = new Client(
       "OnMMoZ6YVozrgSBeZ9FpkC0ixH0ycYZn",
       array(
         "consumer" => "fork_curl",
diff --git a/test/ConsumerLibCurlTest.php b/test/ConsumerLibCurlTest.php
index 8fd1a4b..75f8e01 100644
--- a/test/ConsumerLibCurlTest.php
+++ b/test/ConsumerLibCurlTest.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once __DIR__ . "/../lib/PostHog/Client.php";
+use PostHog\Client;
 
 class ConsumerLibCurlTest extends PHPUnit\Framework\TestCase
 {
@@ -9,7 +9,7 @@ class ConsumerLibCurlTest extends PHPUnit\Framework\TestCase
   public function setUp(): void
   {
     date_default_timezone_set("UTC");
-    $this->client = new PostHog_Client(
+    $this->client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "consumer" => "lib_curl",
diff --git a/test/ConsumerSocketTest.php b/test/ConsumerSocketTest.php
index 56d9873..5165431 100644
--- a/test/ConsumerSocketTest.php
+++ b/test/ConsumerSocketTest.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once __DIR__ . "/../lib/PostHog/Client.php";
+use PostHog\Client;
 
 class ConsumerSocketTest extends PHPUnit\Framework\TestCase
 {
@@ -13,7 +13,7 @@ public function setUp(): void
 
   public function testCapture()
   {
-    $client = new PostHog_Client(
+    $client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "consumer" => "socket",
@@ -28,7 +28,7 @@ public function testCapture()
 
   public function testIdentify()
   {
-    $client = new PostHog_Client(
+    $client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "consumer" => "socket",
@@ -46,7 +46,7 @@ public function testIdentify()
 
   public function testShortTimeout()
   {
-    $client = new PostHog_Client(
+    $client = new Client(
       "BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg",
       array(
         "timeout" => 0.01,
@@ -69,7 +69,7 @@ public function testShortTimeout()
 
   public function testProductionProblems()
   {
-    $client = new PostHog_Client("x",
+    $client = new Client("x",
       array(
         "consumer" => "socket",
         "error_handler" => function () {
@@ -92,7 +92,7 @@ public function testLargeMessage()
       "consumer" => "socket",
     );
 
-    $client = new PostHog_Client("BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg", $options);
+    $client = new Client("BrpS4SctoaCCsyjlnlun3OzyNJAafdlv__jUWaaJWXg", $options);
 
     $big_property = "";
 
@@ -112,7 +112,7 @@ public function testLargeMessage()
   public function testConnectionError()
   {
     $this->expectException('RuntimeException');
-    $client = new PostHog_Client("x", array(
+    $client = new Client("x", array(
       "consumer" => "socket",
       "host" => "t.posthog.comcomcom",
       "error_handler" => function ($errno, $errmsg) {
diff --git a/test/PostHogTest.php b/test/PostHogTest.php
index 5285f08..ae6fcc0 100644
--- a/test/PostHogTest.php
+++ b/test/PostHogTest.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once __DIR__ . "/../lib/PostHog.php";
+use PostHog\PostHog;
 
 class PostHogTest extends PHPUnit\Framework\TestCase
 {