diff --git a/Gruntfile.js b/Gruntfile.js
index e2360ca944..c21d351790 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -211,6 +211,7 @@ module.exports = function (grunt) {
                     'daemon.php',
                     'rebuild.php',
                     'clear_cache.php',
+                    'preload.php',
                     'upgrade.php',
                     'extension.php',
                     'websocket.php',
diff --git a/application/Espo/Core/ApplicationRunners/Preload.php b/application/Espo/Core/ApplicationRunners/Preload.php
new file mode 100644
index 0000000000..78f81c912d
--- /dev/null
+++ b/application/Espo/Core/ApplicationRunners/Preload.php
@@ -0,0 +1,50 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2020 Yuri Kuznetsov, Taras Machyshyn, Oleksiy Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Core\ApplicationRunners;
+
+use Espo\Core\{
+    Utils\Preload as PreloadUtil,
+};
+
+/**
+ * Runs a preload.
+ *
+ * @see https://www.php.net/manual/en/opcache.preloading.php
+ */
+class Preload implements ApplicationRunner
+{
+    use Cli;
+
+    public function run()
+    {
+        $preload = new PreloadUtil();
+        $preload->process();
+    }
+}
diff --git a/application/Espo/Core/Utils/Preload.php b/application/Espo/Core/Utils/Preload.php
new file mode 100644
index 0000000000..1f67f89638
--- /dev/null
+++ b/application/Espo/Core/Utils/Preload.php
@@ -0,0 +1,131 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2020 Yuri Kuznetsov, Taras Machyshyn, Oleksiy Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Core\Utils;
+
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RegexIterator;
+use RecursiveRegexIterator;
+
+use Throwable;
+
+/**
+ * Scans all PHP files and loads them. Used for a preloading.
+ *
+ * @see https://www.php.net/manual/en/opcache.preloading.php
+ */
+class Preload
+{
+    protected $dirList = [
+        'application',
+        'vendor/slim',
+        'vendor/nikic/fast-route',
+    ];
+
+    private $counter = 0;
+
+    protected $ignoreList = [
+        'application/Espo/Core/Mail/Parsers/PhpMimeMailParser/',
+        'vendor/nikic/fast-route/test',
+    ];
+
+    public function process()
+    {
+        foreach ($this->dirList as $dir) {
+            $this->processForDir($dir);
+        }
+
+        echo "Success." . PHP_EOL;
+        echo "Files preloaded: " . (string) $this->counter . "." . PHP_EOL;
+    }
+
+    protected function processForDir(string $dir)
+    {
+        $directory = new RecursiveDirectoryIterator($dir);
+        $fullTree = new RecursiveIteratorIterator($directory);
+        $phpFiles = new RegexIterator($fullTree, '/.+((?<!Test)+\.php$)/i', RecursiveRegexIterator::GET_MATCH);
+
+        foreach ($phpFiles as $key => $file) {
+            $this->processFile($file[0]);
+        }
+    }
+
+    protected function processFile(string $file)
+    {
+        if ($this->isFileToBeIgnored($file)) {
+            return;
+        }
+
+        try {
+            require_once($file);
+
+            $this->counter ++;
+        }
+        catch (Throwable $e) {
+            $this->processException($e);
+
+            throw $e;
+        }
+    }
+
+    protected function processException(Throwable $e)
+    {
+        echo "Error occured." . PHP_EOL;
+
+        $msg = $e->getMessage();
+
+        if ($msg) {
+            echo "Message: {$msg}" . PHP_EOL;
+        }
+
+        $file = $e->getFile();
+
+        if ($file) {
+            echo "File: {$file}" . PHP_EOL;
+        }
+
+        echo "Line: " . $e->getLine() . PHP_EOL;
+    }
+
+    protected function isFileToBeIgnored(string $file) : bool
+    {
+        $file = str_replace('\\', '/', $file);
+
+        foreach ($this->ignoreList as $item) {
+            if (strpos($file, $item) === 0) {
+                return true;
+            }
+        }
+
+        return false;
+
+        return in_array($file, $this->ignoreList);
+    }
+}
diff --git a/preload.php b/preload.php
new file mode 100644
index 0000000000..3c4cdaad9c
--- /dev/null
+++ b/preload.php
@@ -0,0 +1,45 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2020 Yuri Kuznetsov, Taras Machyshyn, Oleksiy Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+/**
+ * Preloads PHP files. Can be also used to check the syntax.
+ *
+ * @see https://www.php.net/manual/en/opcache.preloading.php
+ *
+ * Important: Preloading must be disabled before upgrading and extension installation.
+ */
+
+include "bootstrap.php";
+
+use Espo\Core\{
+    Application,
+    ApplicationRunners\Preload,
+};
+
+(new Application())->run(Preload::class);