diff --git a/App.php b/App.php
new file mode 100644
index 0000000..813abe3
--- /dev/null
+++ b/App.php
@@ -0,0 +1,116 @@
+<?php
+
+/**
+ * SPDX-License-Identifier: EUPL-1.2
+ * Authors: see /README.md
+ */
+
+namespace SeaCMS;
+
+use Exception;
+use Pico;
+use Throwable;
+
+set_error_handler(function (
+    int $errno,
+    string $errstr,
+    string $errfile = '',
+    int $errline = -1
+) {
+    if (!isset($GLOBALS['errorMessages'])){
+        $GLOBALS['errorMessages']= [];
+    }
+    $GLOBALS['errorMessages'][] = <<<HTML
+    <div>
+    Error : $errstr<br>
+    in file '$errfile' (line '$errline').<br/>
+    ErrCode : $errno
+    </div>
+
+    HTML;
+    return true;
+});
+
+class App 
+{
+    /**
+     * Pico instance.
+     * @var Pico
+     */
+    protected $pico;
+
+    public function __construct(string $contentFolderFromRoot)
+    {
+        // sanitize content folder
+        $cwd = getcwd();
+        if (empty($contentFolderFromRoot)){
+            $contentFolderFromRoot = 'content';
+        } else {
+            $contentFolderFromRoot = str_replace('\\','/',$contentFolderFromRoot);
+        }
+        if (!is_dir($cwd)){
+            throw new Exception("getcwd returned a path that is not a directory !");
+        }
+        if (!is_dir("$cwd/$contentFolderFromRoot")){
+            $contentFolderFromRoot = 'vendor/picocms/pico/content-sample';
+        }
+        if (substr($contentFolderFromRoot,-1) !== '/'){
+            $contentFolderFromRoot .= '/';
+        }
+        // instance Pico
+        $this->pico = new Pico(
+            $cwd,    // root dir
+            $contentFolderFromRoot,  // config dir
+            'vendor/picocms/plugins/', // plugins dir
+            'vendor/picocms/themes/'   // themes dir
+        );
+    }
+
+    public function runPico(): string
+    {
+        return $this->pico->run();
+    }
+    
+    /**
+     * instanciate Pico and run it then echo output
+     * @param string $contentFolderFromRoot where is the root folder
+     */
+    public static function run(string $contentFolderFromRoot)
+    {
+        try {
+            $app = new App($contentFolderFromRoot);
+            $output = $app->runPico();
+            self::appendErrorMessagesIfNeeded($output);
+        } catch (Throwable $th) {
+            $output = <<<HTML
+            <div style="color:red;">
+                Exception : {$th->__toString()}
+            </div>
+            HTML;
+        } finally {
+            echo $output;
+        }
+    }
+
+    /**
+     * append error messages from $GLOBALS['errorMessages']
+     * only if $_GET['debug'] === 'yes'
+     * @param string &$output
+     */
+    protected static function appendErrorMessagesIfNeeded(string &$output)
+    {
+        if (!empty($_GET['debug']) && $_GET['debug'] === 'yes' && !empty($GLOBALS['errorMessages'])){
+            $formattedMessages = implode("\n", $GLOBALS['errorMessages']);
+            $formattedMessages = <<<HTML
+            <div style="background-color:navajowhite;">
+                $formattedMessages
+            </div>
+            HTML;
+            if (preg_match('/<\/body>/i', $output, $match)) {
+                $output = str_replace($match[0], $formattedMessages.$match[0], $output);
+            } else {
+                $output = $output.$formattedMessages;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 79c30b0..e43a632 100644
--- a/composer.json
+++ b/composer.json
@@ -29,6 +29,9 @@
     "suggest": {
         "picocms/pico-theme": "Default pico theme : revision ^3.0"
     },
+    "autoload": {
+        "classmap": ["App.php"]
+    },
     "extra": {
         "pico-plugin-dir": "vendor/picocms/plugins/",
         "pico-theme-dir": "vendor/picocms/themes/"
