diff --git a/system/src/Grav/Common/Grav.php b/system/src/Grav/Common/Grav.php
index 64946113d..4f87a7642 100644
--- a/system/src/Grav/Common/Grav.php
+++ b/system/src/Grav/Common/Grav.php
@@ -63,6 +63,7 @@ class Grav extends Container
         'Grav\Common\Service\ConfigServiceProvider',
         'Grav\Common\Service\ErrorServiceProvider',
         'Grav\Common\Service\FilesystemServiceProvider',
+        'Grav\Common\Service\FlexServiceProvider',
         'Grav\Common\Service\InflectorServiceProvider',
         'Grav\Common\Service\LoggerServiceProvider',
         'Grav\Common\Service\OutputServiceProvider',
diff --git a/system/src/Grav/Common/Service/FlexServiceProvider.php b/system/src/Grav/Common/Service/FlexServiceProvider.php
new file mode 100644
index 000000000..ba9607976
--- /dev/null
+++ b/system/src/Grav/Common/Service/FlexServiceProvider.php
@@ -0,0 +1,91 @@
+<?php
+
+/**
+ * @package    Grav\Common\Service
+ *
+ * @copyright  Copyright (C) 2015 - 2020 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Common\Service;
+
+use Grav\Common\Config\Config;
+use Grav\Common\Flex\Users\Storage\UserFolderStorage;
+use Grav\Common\Grav;
+use Grav\Events\FlexRegisterEvent;
+use Grav\Framework\Flex\Flex;
+use Pimple\Container;
+use Pimple\ServiceProviderInterface;
+
+class FlexServiceProvider implements ServiceProviderInterface
+{
+    public function register(Container $container)
+    {
+        $container['flex'] = function (Grav $container) {
+            /** @var Config $config */
+            $config = $container['config'];
+
+            $flex = new Flex([], ['object' => $config->get('system.flex', [])]);
+
+            $accountsEnabled = $config->get('system.accounts.type', 'regular') === 'flex';
+            $pagesEnabled = $config->get('system.pages.type', 'regular') === 'flex';
+
+            // Add built-in types from Grav.
+            if ($pagesEnabled) {
+                $flex->addDirectoryType(
+                    'grav-pages',
+                    'blueprints://flex/pages.yaml',
+                    [
+                        'enabled' => $pagesEnabled
+                    ]
+                );
+            }
+            if ($accountsEnabled) {
+                $flex->addDirectoryType(
+                    'grav-accounts',
+                    'blueprints://flex/accounts.yaml',
+                    [
+                        'enabled' => $accountsEnabled,
+                        'data' => [
+                            'storage' => $this->getFlexAccountsStorage($config),
+                        ]
+                    ]
+                );
+                $flex->addDirectoryType(
+                    'grav-user-groups',
+                    'blueprints://flex/user-groups.yaml',
+                    [
+                        'enabled' => $accountsEnabled
+                    ]
+                );
+            }
+
+            // Call event to register Flex Directories.
+            $event = new FlexRegisterEvent($flex);
+            $container->dispatchEvent($event);
+
+            return $flex;
+        };
+    }
+
+    private function getFlexAccountsStorage(Config $config)
+    {
+        $value = $config->get('system.accounts.storage', 'file');
+        if (\is_array($value)) {
+            return $value;
+        }
+
+        if ($value === 'folder') {
+            return [
+                'class' => UserFolderStorage::class,
+                'options' => [
+                    'file' => 'user',
+                    'pattern' => '{FOLDER}/{KEY:2}/{KEY}/{FILE}{EXT}',
+                    'key' => 'storage_key',
+                ],
+            ];
+        }
+
+        return [];
+    }
+}
diff --git a/system/src/Grav/Events/FlexRegisterEvent.php b/system/src/Grav/Events/FlexRegisterEvent.php
new file mode 100644
index 000000000..406a2f149
--- /dev/null
+++ b/system/src/Grav/Events/FlexRegisterEvent.php
@@ -0,0 +1,44 @@
+<?php
+
+/**
+ * @package    Grav\Events
+ *
+ * @copyright  Copyright (C) 2015 - 2020 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Events;
+
+use Grav\Framework\Flex\Flex;
+
+/**
+ * Flex Register Event
+ *
+ * This event is called the first time $grav['flex'] is being called.
+ *
+ * Use this event to register enabled Directories to Flex.
+ *
+ * @property Flex $flex Flex instance.
+ */
+class FlexRegisterEvent
+{
+    /** @var Flex */
+    public $flex;
+
+    /**
+     * FlexRegisterEvent constructor.
+     * @param Flex $flex
+     */
+    public function __construct(Flex $flex)
+    {
+        $this->flex = $flex;
+    }
+
+    /**
+     * @return array
+     */
+    public function __debugInfo(): array
+    {
+        return (array)$this;
+    }
+}
diff --git a/system/src/Grav/Framework/Flex/Flex.php b/system/src/Grav/Framework/Flex/Flex.php
index bdf44f053..da0abf8a3 100644
--- a/system/src/Grav/Framework/Flex/Flex.php
+++ b/system/src/Grav/Framework/Flex/Flex.php
@@ -14,6 +14,7 @@ namespace Grav\Framework\Flex;
 use Grav\Common\Debugger;
 use Grav\Common\Grav;
 use Grav\Framework\Flex\Interfaces\FlexCollectionInterface;
+use Grav\Framework\Flex\Interfaces\FlexInterface;
 use Grav\Framework\Flex\Interfaces\FlexObjectInterface;
 use Grav\Framework\Object\ObjectCollection;
 
@@ -21,7 +22,7 @@ use Grav\Framework\Object\ObjectCollection;
  * Class Flex
  * @package Grav\Framework\Flex
  */
-class Flex implements \Countable
+class Flex implements FlexInterface
 {
     /** @var array */
     protected $config;
diff --git a/system/src/Grav/Framework/Flex/Interfaces/FlexInterface.php b/system/src/Grav/Framework/Flex/Interfaces/FlexInterface.php
new file mode 100644
index 000000000..64c4c7b43
--- /dev/null
+++ b/system/src/Grav/Framework/Flex/Interfaces/FlexInterface.php
@@ -0,0 +1,96 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @package    Grav\Framework\Flex
+ *
+ * @copyright  Copyright (C) 2015 - 2020 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\Flex\Interfaces;
+
+use Grav\Framework\Flex\FlexDirectory;
+
+/**
+ * Interface FlexInterface
+ * @package Grav\Framework\Flex\Interfaces
+ */
+interface FlexInterface extends \Countable
+{
+    /**
+     * @param string $type
+     * @param string $blueprint
+     * @param array  $config
+     * @return $this
+     */
+    public function addDirectoryType(string $type, string $blueprint, array $config = []);
+
+    /**
+     * @param FlexDirectory $directory
+     * @return $this
+     */
+    public function addDirectory(FlexDirectory $directory);
+
+    /**
+     * @param string $type
+     * @return bool
+     */
+    public function hasDirectory(string $type): bool;
+
+    /**
+     * @param array|string[]|null $types
+     * @param bool $keepMissing
+     * @return array<FlexDirectory|null>
+     */
+    public function getDirectories(array $types = null, bool $keepMissing = false): array;
+
+    /**
+     * @param string $type
+     * @return FlexDirectory|null
+     */
+    public function getDirectory(string $type): ?FlexDirectory;
+
+    /**
+     * @param string $type
+     * @param array|null $keys
+     * @param string|null $keyField
+     * @return FlexCollectionInterface|null
+     */
+    public function getCollection(string $type, array $keys = null, string $keyField = null): ?FlexCollectionInterface;
+
+    /**
+     * @param array $keys
+     * @param array $options            In addition to the options in getObjects(), following options can be passed:
+     *                                  collection_class:   Class to be used to create the collection. Defaults to ObjectCollection.
+     * @return FlexCollectionInterface
+     * @throws \RuntimeException
+     */
+    public function getMixedCollection(array $keys, array $options = []): FlexCollectionInterface;
+
+    /**
+     * @param array $keys
+     * @param array $options    Following optional options can be passed:
+     *                          types:          List of allowed types.
+     *                          type:           Allowed type if types isn't defined, otherwise acts as default_type.
+     *                          default_type:   Set default type for objects given without type (only used if key_field isn't set).
+     *                          keep_missing:   Set to true if you want to return missing objects as null.
+     *                          key_field:      Key field which is used to match the objects.
+     * @return array
+     */
+    public function getObjects(array $keys, array $options = []): array;
+
+    /**
+     * @param string $key
+     * @param string|null $type
+     * @param string|null $keyField
+     * @return FlexObjectInterface|null
+     */
+    public function getObject(string $key, string $type = null, string $keyField = null): ?FlexObjectInterface;
+
+    /**
+     * @return int
+     */
+    public function count(): int;
+}