diff --git a/src/Core/CoreServiceProvider.php b/src/Core/CoreServiceProvider.php
index 8f71be596..6f63cd6de 100644
--- a/src/Core/CoreServiceProvider.php
+++ b/src/Core/CoreServiceProvider.php
@@ -13,7 +13,6 @@ use Flarum\Core\Models\Discussion;
 use Flarum\Core\Search\GambitManager;
 use Flarum\Core\Events\RegisterDiscussionGambits;
 use Flarum\Core\Events\RegisterUserGambits;
-use Flarum\Extend\Permission;
 use Flarum\Extend\ActivityType;
 use Flarum\Extend\NotificationType;
 use Flarum\Extend\Locale;
diff --git a/src/Extend/AdminClient.php b/src/Extend/AdminClient.php
new file mode 100644
index 000000000..b12e82ae5
--- /dev/null
+++ b/src/Extend/AdminClient.php
@@ -0,0 +1,34 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Contracts\Container\Container;
+use Flarum\Admin\Actions\IndexAction;
+
+class AdminClient implements ExtenderInterface
+{
+    protected $assets = [];
+
+    protected $translations = [];
+
+    public function assets($assets)
+    {
+        $this->assets = array_merge($this->assets, $assets);
+
+        return $this;
+    }
+
+    public function translations($keys)
+    {
+        $this->translations = array_merge($this->translations, $keys);
+
+        return $this;
+    }
+
+    public function extend(Container $container)
+    {
+        $container->make('events')->listen('Flarum\Admin\Events\RenderView', function ($event) {
+            $event->assets->addFiles($this->assets);
+        });
+
+        IndexAction::$translations = array_merge(IndexAction::$translations, $this->translations);
+    }
+}
diff --git a/src/Extend/AdminTranslations.php b/src/Extend/AdminTranslations.php
deleted file mode 100644
index bea1f8fbb..000000000
--- a/src/Extend/AdminTranslations.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-
-class AdminTranslations implements ExtenderInterface
-{
-    protected $keys;
-
-    public function __construct($keys)
-    {
-        $this->keys = $keys;
-    }
-
-    public function extend(Container $container)
-    {
-
-    }
-}
diff --git a/src/Extend/ApiAction.php b/src/Extend/ApiAction.php
new file mode 100644
index 000000000..cd2f25951
--- /dev/null
+++ b/src/Extend/ApiAction.php
@@ -0,0 +1,143 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Contracts\Container\Container;
+
+class ApiAction implements ExtenderInterface
+{
+    protected $action;
+
+    protected $serializer;
+
+    protected $addInclude = [];
+
+    protected $removeInclude = [];
+
+    protected $addLink = [];
+
+    protected $removeLink = [];
+
+    protected $limitMax;
+
+    protected $limit;
+
+    protected $addSortFields = [];
+
+    protected $removeSortFields = [];
+
+    protected $sort;
+
+    public function __construct($action)
+    {
+        $this->action = $action;
+    }
+
+    public function serializer($serializer)
+    {
+        $this->serializer = $serializer;
+
+        return $this;
+    }
+
+    public function addInclude($relation, $default = true)
+    {
+        $this->addInclude[] = compact('relation', 'default');
+
+        return $this;
+    }
+
+    public function removeInclude($relation)
+    {
+        $this->removeInclude[] = $relation;
+
+        return $this;
+    }
+
+    public function addLink($relation)
+    {
+        $this->addLink[] = $relation;
+
+        return $this;
+    }
+
+    public function removeLink($relation)
+    {
+        $this->removeLink[] = $relation;
+
+        return $this;
+    }
+
+    public function limitMax($limitMax)
+    {
+        $this->limitMax = $limitMax;
+
+        return $this;
+    }
+
+    public function limit($limit)
+    {
+        $this->limit = $limit;
+
+        return $this;
+    }
+
+    public function addSortField($field)
+    {
+        $this->addSortFields[] = $field;
+
+        return $this;
+    }
+
+    public function removeSortField($field)
+    {
+        $this->removeSortFields[] = $field;
+
+        return $this;
+    }
+
+    public function sort($sort)
+    {
+        $this->sort = $sort;
+
+        return $this;
+    }
+
+    public function extend(Container $container)
+    {
+        foreach ((array) $this->action as $action) {
+            if ($this->serializer) {
+                $action::$serializer = $this->serializer;
+            }
+            foreach ($this->addInclude as $include) {
+                $action::$include[$include['relation']] = $include['default'];
+            }
+            foreach ($this->removeInclude as $relation) {
+                unset($action::$include[$relation]);
+            }
+            foreach ($this->addLink as $relation) {
+                $action::$link[] = $relation;
+            }
+            foreach ($this->removeLink as $relation) {
+                if (($k = array_search($relation, $action::$link)) !== false) {
+                    unset($action::$link[$k]);
+                }
+            }
+            if ($this->limitMax) {
+                $action::$limitMax = $this->limitMax;
+            }
+            if ($this->limit) {
+                $action::$limit = $this->limit;
+            }
+            foreach ($this->addSortFields as $field) {
+                $action::$sortFields[] = $field;
+            }
+            foreach ($this->removeSortFields as $field) {
+                if (($k = array_search($field, $action::$sortFields)) !== false) {
+                    unset($action::$sortFields[$k]);
+                }
+            }
+            if ($this->sort) {
+                $action::$sort = $this->sort;
+            }
+        }
+    }
+}
diff --git a/src/Extend/ApiInclude.php b/src/Extend/ApiInclude.php
deleted file mode 100644
index 4336f69f8..000000000
--- a/src/Extend/ApiInclude.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-
-class ApiInclude implements ExtenderInterface
-{
-    protected $actions;
-
-    protected $relationships;
-
-    protected $status;
-
-    public function __construct($actions, $relationships, $status = false)
-    {
-        $this->actions = $actions;
-        $this->relationships = $relationships;
-        $this->status = $status;
-    }
-
-    public function extend(Container $container)
-    {
-        foreach ((array) $this->actions as $action) {
-            $parts = explode('.', $action);
-            $class = 'Flarum\Api\Actions\\'.ucfirst($parts[0]).'\\'.ucfirst($parts[1]).'Action';
-
-            foreach ((array) $this->relationships as $relationship) {
-                if (is_null($this->status)) {
-                    unset($class::$include[$relationship]);
-                } else {
-                    $class::$include[$relationship] = $this->status;
-                }
-            }
-        }
-    }
-}
diff --git a/src/Extend/ApiLink.php b/src/Extend/ApiLink.php
deleted file mode 100644
index cc592d262..000000000
--- a/src/Extend/ApiLink.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-
-class ApiLink implements ExtenderInterface
-{
-    protected $actions;
-
-    protected $relationships;
-
-    public function __construct($actions, $relationships)
-    {
-        $this->actions = $actions;
-        $this->relationships = $relationships;
-    }
-
-    public function extend(Container $container)
-    {
-        foreach ((array) $this->actions as $action) {
-            $parts = explode('.', $action);
-            $class = 'Flarum\Api\Actions\\'.ucfirst($parts[0]).'\\'.ucfirst($parts[1]).'Action';
-
-            foreach ((array) $this->relationships as $relationship) {
-                $class::$link[] = $relationship;
-            }
-        }
-    }
-}
diff --git a/src/Extend/ApiSerializer.php b/src/Extend/ApiSerializer.php
new file mode 100644
index 000000000..14010c745
--- /dev/null
+++ b/src/Extend/ApiSerializer.php
@@ -0,0 +1,61 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Contracts\Container\Container;
+
+class ApiSerializer implements ExtenderInterface
+{
+    protected $serializer;
+
+    protected $attributes = [];
+
+    protected $relations = [];
+
+    public function __construct($serializer)
+    {
+        $this->serializer = $serializer;
+    }
+
+    public function attributes($callback)
+    {
+        $this->attributes[] = $callback;
+
+        return $this;
+    }
+
+    public function hasOne($relation, $related)
+    {
+        $this->relations[$relation] = function ($serializer) use ($relation, $related) {
+            return $serializer->hasOne($related, $relation);
+        };
+
+        return $this;
+    }
+
+    public function hasMany($relation, $related)
+    {
+        $this->relations[$relation] = function ($serializer) use ($relation, $related) {
+            return $serializer->hasMany($related, $relation);
+        };
+
+        return $this;
+    }
+
+    public function extend(Container $container)
+    {
+        $serializer = $this->serializer;
+
+        if (count($this->attributes)) {
+            $container->make('events')->listen('Flarum\Api\Events\SerializeAttributes', function ($event) use ($serializer) {
+                if ($event->serializer instanceof $serializer) {
+                    foreach ($this->attributes as $callback) {
+                        $callback($event->attributes, $event->model, $event->serializer->actor->getUser());
+                    }
+                }
+            });
+        }
+
+        foreach ($this->relations as $relation => $callback) {
+            $serializer::addRelationship($relation, $callback);
+        }
+    }
+}
diff --git a/src/Extend/EventSubscribers.php b/src/Extend/EventSubscriber.php
similarity index 50%
rename from src/Extend/EventSubscribers.php
rename to src/Extend/EventSubscriber.php
index c8c391a1c..27b129afc 100644
--- a/src/Extend/EventSubscribers.php
+++ b/src/Extend/EventSubscriber.php
@@ -2,18 +2,18 @@
 
 use Illuminate\Contracts\Container\Container;
 
-class EventSubscribers implements ExtenderInterface
+class EventSubscriber implements ExtenderInterface
 {
-    protected $subscribers;
+    protected $subscriber;
 
-    public function __construct($subscribers)
+    public function __construct($subscriber)
     {
-        $this->subscribers = $subscribers;
+        $this->subscriber = $subscriber;
     }
 
     public function extend(Container $container)
     {
-        foreach ((array) $this->subscribers as $subscriber) {
+        foreach ((array) $this->subscriber as $subscriber) {
             $container->make('events')->subscribe($subscriber);
         }
     }
diff --git a/src/Extend/ForumAssets.php b/src/Extend/ForumAssets.php
deleted file mode 100644
index 1294d94fd..000000000
--- a/src/Extend/ForumAssets.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-
-class ForumAssets implements ExtenderInterface
-{
-    protected $files;
-
-    public function __construct($files)
-    {
-        $this->files = $files;
-    }
-
-    public function extend(Container $container)
-    {
-        $container->make('events')->listen('Flarum\Forum\Events\RenderView', function ($event) {
-            $event->assets->addFiles($this->files);
-        });
-    }
-}
diff --git a/src/Extend/ForumClient.php b/src/Extend/ForumClient.php
new file mode 100644
index 000000000..fba5642ea
--- /dev/null
+++ b/src/Extend/ForumClient.php
@@ -0,0 +1,34 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Contracts\Container\Container;
+use Flarum\Forum\Actions\IndexAction;
+
+class ForumClient implements ExtenderInterface
+{
+    protected $assets = [];
+
+    protected $translations = [];
+
+    public function assets($assets)
+    {
+        $this->assets = array_merge($this->assets, $assets);
+
+        return $this;
+    }
+
+    public function translations($keys)
+    {
+        $this->translations = array_merge($this->translations, $keys);
+
+        return $this;
+    }
+
+    public function extend(Container $container)
+    {
+        $container->make('events')->listen('Flarum\Forum\Events\RenderView', function ($event) {
+            $event->assets->addFiles($this->assets);
+        });
+
+        IndexAction::$translations = array_merge(IndexAction::$translations, $this->translations);
+    }
+}
diff --git a/src/Extend/ForumTranslations.php b/src/Extend/ForumTranslations.php
deleted file mode 100644
index 1e56c2a14..000000000
--- a/src/Extend/ForumTranslations.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-use Flarum\Forum\Actions\IndexAction;
-
-class ForumTranslations implements ExtenderInterface
-{
-    protected $keys;
-
-    public function __construct($keys)
-    {
-        $this->keys = $keys;
-    }
-
-    public function extend(Container $container)
-    {
-        IndexAction::$translations = array_merge(IndexAction::$translations, $this->keys);
-    }
-}
diff --git a/src/Extend/Model.php b/src/Extend/Model.php
new file mode 100644
index 000000000..7cf2fa6af
--- /dev/null
+++ b/src/Extend/Model.php
@@ -0,0 +1,87 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Contracts\Container\Container;
+use Closure;
+
+class Model implements ExtenderInterface
+{
+    protected $model;
+
+    protected $scopeVisible = [];
+
+    protected $allow = [];
+
+    protected $relations = [];
+
+    public function __construct($model)
+    {
+        $this->model = $model;
+    }
+
+    public function scopeVisible(Closure $callback)
+    {
+        $this->scopeVisible[] = $callback;
+
+        return $this;
+    }
+
+    public function allow($action, Closure $callback)
+    {
+        $this->allow[] = compact('action', 'callback');
+
+        return $this;
+    }
+
+    public function hasOne($relation, $related, $foreignKey = null, $localKey = null)
+    {
+        $this->relations[$relation] = function ($model) use ($relation, $related, $foreignKey, $localKey) {
+            return $model->hasOne($related, $foreignKey, $localKey, $relation);
+        };
+
+        return $this;
+    }
+
+    public function belongsTo($relation, $related, $foreignKey = null, $otherKey = null)
+    {
+        $this->relations[$relation] = function ($model) use ($relation, $related, $foreignKey, $otherKey) {
+            return $model->belongsTo($related, $foreignKey, $otherKey, $relation);
+        };
+
+        return $this;
+    }
+
+    public function hasMany($relation, $related, $foreignKey = null, $localKey = null)
+    {
+        $this->relations[$relation] = function ($model) use ($relation, $related, $foreignKey, $localKey) {
+            return $model->hasMany($related, $foreignKey, $localKey, $relation);
+        };
+
+        return $this;
+    }
+
+    public function belongsToMany($relation, $related, $table = null, $foreignKey = null, $otherKey = null)
+    {
+        $this->relations[$relation] = function ($model) use ($relation, $related, $table, $foreignKey, $otherKey) {
+            return $model->belongsToMany($related, $table, $foreignKey, $otherKey, $relation);
+        };
+
+        return $this;
+    }
+
+    public function extend(Container $container)
+    {
+        $model = $this->model;
+
+        foreach ($this->relations as $relation => $callback) {
+            $model::addRelationship($relation, $callback);
+        }
+
+        foreach ($this->scopeVisible as $callback) {
+            $model::scopeVisible($callback);
+        }
+
+        foreach ($this->allow as $info) {
+            $model::allow($info['action'], $info['callback']);
+        }
+    }
+}
diff --git a/src/Extend/Relationship.php b/src/Extend/Relationship.php
deleted file mode 100644
index a5e817f82..000000000
--- a/src/Extend/Relationship.php
+++ /dev/null
@@ -1,42 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-use Closure;
-
-class Relationship implements ExtenderInterface
-{
-    protected $parent;
-
-    protected $name;
-
-    protected $type;
-
-    protected $child;
-
-    protected $table;
-
-    public function __construct($parent, $name, $type, $child = null)
-    {
-        $this->parent = $parent;
-        $this->name = $name;
-        $this->type = $type;
-        $this->child = $child;
-    }
-
-    public function extend(Container $container)
-    {
-        $parent = $this->parent;
-
-        $parent::addRelationship($this->name, function ($model) {
-            if ($this->type instanceof Closure) {
-                return call_user_func($this->type, $model);
-            } elseif ($this->type === 'belongsTo') {
-                return $model->belongsTo($this->child, null, null, $this->name);
-            } elseif ($this->type === 'belongsToMany') {
-                return $model->belongsToMany($this->child, $this->table, null, null, $this->name);
-            } else {
-                // @todo
-            }
-        });
-    }
-}
diff --git a/src/Extend/SerializeAttributes.php b/src/Extend/SerializeAttributes.php
deleted file mode 100644
index e3d314889..000000000
--- a/src/Extend/SerializeAttributes.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-
-class SerializeAttributes implements ExtenderInterface
-{
-    protected $serializer;
-
-    protected $callback;
-
-    public function __construct($serializer, $callback)
-    {
-        $this->serializer = $serializer;
-        $this->callback = $callback;
-    }
-
-    public function extend(Container $container)
-    {
-        $container->make('events')->listen('Flarum\Api\Events\SerializeAttributes', function ($event) {
-            if ($event->serializer instanceof $this->serializer) {
-                call_user_func_array($this->callback, [&$event->attributes, $event->model, $event->serializer]);
-            }
-        });
-    }
-}
diff --git a/src/Extend/SerializeRelationship.php b/src/Extend/SerializeRelationship.php
deleted file mode 100644
index 3d52e0ea7..000000000
--- a/src/Extend/SerializeRelationship.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php namespace Flarum\Extend;
-
-use Illuminate\Contracts\Container\Container;
-use Closure;
-
-class SerializeRelationship implements ExtenderInterface
-{
-    protected $parent;
-
-    protected $type;
-
-    protected $name;
-
-    protected $child;
-
-    public function __construct($parent, $type, $name, $child = null)
-    {
-        $this->parent = $parent;
-        $this->type = $type;
-        $this->name = $name;
-        $this->child = $child;
-    }
-
-    public function extend(Container $container)
-    {
-        $parent = $this->parent;
-
-        $parent::addRelationship($this->name, function ($serializer) {
-            if ($this->type instanceof Closure) {
-                return $this->type();
-            } else {
-                return $serializer->{$this->type}($this->child, $this->name);
-            }
-        });
-    }
-}
diff --git a/src/Forum/Actions/IndexAction.php b/src/Forum/Actions/IndexAction.php
index 215ce902f..53ec01873 100644
--- a/src/Forum/Actions/IndexAction.php
+++ b/src/Forum/Actions/IndexAction.php
@@ -60,7 +60,7 @@ class IndexAction extends HtmlAction
             // manually?
             $response = $this->apiClient->send('Flarum\Api\Actions\Users\ShowAction', ['id' => $user->id]);
 
-            $data = [$response->data];
+            $data[] = $response->data;
             if (isset($response->included)) {
                 $data = array_merge($data, $response->included);
             }
diff --git a/src/Forum/ForumServiceProvider.php b/src/Forum/ForumServiceProvider.php
index f6e64a1e5..f79fa639d 100644
--- a/src/Forum/ForumServiceProvider.php
+++ b/src/Forum/ForumServiceProvider.php
@@ -1,6 +1,5 @@
 <?php namespace Flarum\Forum;
 
-use Flarum\Extend\ForumTranslations;
 use Flarum\Http\RouteCollection;
 use Flarum\Http\UrlGenerator;
 use Flarum\Support\AssetManager;
@@ -44,12 +43,6 @@ class ForumServiceProvider extends ServiceProvider
         ]);
 
         $this->routes();
-
-        $this->extend(
-            new ForumTranslations([
-                //
-            ])
-        );
     }
 
     protected function routes()