diff --git a/assignment-client/src/Agent.cpp b/assignment-client/src/Agent.cpp
index 3937d5f799..68464fef91 100644
--- a/assignment-client/src/Agent.cpp
+++ b/assignment-client/src/Agent.cpp
@@ -84,7 +84,7 @@ Agent::Agent(ReceivedMessage& message) :
     DependencyManager::get<EntityScriptingInterface>()->setPacketSender(&_entityEditSender);
 
     DependencyManager::set<ResourceManager>();
-    DependencyManager::set<PluginManager>();
+    DependencyManager::set<PluginManager>()->instantiate();
 
     DependencyManager::registerInheritance<SpatialParentFinder, AssignmentParentFinder>();
 
@@ -511,6 +511,7 @@ void Agent::executeScript() {
 
         DependencyManager::set<AssignmentParentFinder>(_entityViewer.getTree());
 
+        DependencyManager::get<ScriptEngines>()->runScriptInitializers(_scriptEngine);
         _scriptEngine->run();
 
         Frame::clearFrameHandler(AUDIO_FRAME_TYPE);
diff --git a/assignment-client/src/AssignmentClientApp.cpp b/assignment-client/src/AssignmentClientApp.cpp
index a87200dc5b..2fa052e244 100644
--- a/assignment-client/src/AssignmentClientApp.cpp
+++ b/assignment-client/src/AssignmentClientApp.cpp
@@ -22,6 +22,7 @@
 #include <HifiConfigVariantMap.h>
 #include <SharedUtil.h>
 #include <ShutdownEventListener.h>
+#include <shared/ScriptInitializerMixin.h>
 
 #include "Assignment.h"
 #include "AssignmentClient.h"
@@ -240,6 +241,7 @@ AssignmentClientApp::AssignmentClientApp(int argc, char* argv[]) :
     QThread::currentThread()->setObjectName("main thread");
 
     DependencyManager::registerInheritance<LimitedNodeList, NodeList>();
+    DependencyManager::set<ScriptInitializers>();
 
     if (numForks || minForks || maxForks) {
         AssignmentClientMonitor* monitor =  new AssignmentClientMonitor(numForks, minForks, maxForks,
diff --git a/assignment-client/src/entities/EntityServer.cpp b/assignment-client/src/entities/EntityServer.cpp
index dde8a01b26..6bbf4a0e3b 100644
--- a/assignment-client/src/entities/EntityServer.cpp
+++ b/assignment-client/src/entities/EntityServer.cpp
@@ -19,6 +19,7 @@
 #include <EntityTree.h>
 #include <ResourceCache.h>
 #include <ScriptCache.h>
+#include <plugins/PluginManager.h>
 #include <EntityEditFilters.h>
 #include <NetworkingConstants.h>
 #include <hfm/ModelFormatRegistry.h>
@@ -41,6 +42,7 @@ EntityServer::EntityServer(ReceivedMessage& message) :
     DependencyManager::set<ResourceManager>();
     DependencyManager::set<ResourceCacheSharedItems>();
     DependencyManager::set<ScriptCache>();
+    DependencyManager::set<PluginManager>()->instantiate();
 
     DependencyManager::registerInheritance<EntityDynamicFactoryInterface, AssignmentDynamicFactory>();
     DependencyManager::set<AssignmentDynamicFactory>();
diff --git a/assignment-client/src/scripts/EntityScriptServer.cpp b/assignment-client/src/scripts/EntityScriptServer.cpp
index 514eb62380..ea002a27c6 100644
--- a/assignment-client/src/scripts/EntityScriptServer.cpp
+++ b/assignment-client/src/scripts/EntityScriptServer.cpp
@@ -64,7 +64,7 @@ EntityScriptServer::EntityScriptServer(ReceivedMessage& message) : ThreadedAssig
     DependencyManager::set<ResourceScriptingInterface>();
 
     DependencyManager::set<ResourceManager>();
-    DependencyManager::set<PluginManager>();
+    DependencyManager::set<PluginManager>()->instantiate();
 
     DependencyManager::registerInheritance<SpatialParentFinder, AssignmentParentFinder>();
 
@@ -462,7 +462,7 @@ void EntityScriptServer::resetEntitiesScriptEngine() {
         _entityViewer.getTree()->update();
     });
 
-
+    scriptEngines->runScriptInitializers(newEngine);
     newEngine->runInThread();
     auto newEngineSP = qSharedPointerCast<EntitiesScriptEngineProvider>(newEngine);
     DependencyManager::get<EntityScriptingInterface>()->setEntitiesScriptEngine(newEngineSP);
diff --git a/cmake/macros/SetupHifiClientServerPlugin.cmake b/cmake/macros/SetupHifiClientServerPlugin.cmake
index bc66484c30..1ce0b0ca6e 100644
--- a/cmake/macros/SetupHifiClientServerPlugin.cmake
+++ b/cmake/macros/SetupHifiClientServerPlugin.cmake
@@ -7,7 +7,8 @@
 #
 macro(SETUP_HIFI_CLIENT_SERVER_PLUGIN)
   set(${TARGET_NAME}_SHARED 1)
-  setup_hifi_library(${ARGV})
+  set(PLUGIN_SUBFOLDER ${ARGN})
+  setup_hifi_library()
 
   if (BUILD_CLIENT)
     add_dependencies(interface ${TARGET_NAME})
@@ -27,6 +28,11 @@ macro(SETUP_HIFI_CLIENT_SERVER_PLUGIN)
     set(SERVER_PLUGIN_PATH "plugins")
   endif()
 
+  if (PLUGIN_SUBFOLDER)
+      set(CLIENT_PLUGIN_PATH "${CLIENT_PLUGIN_PATH}/${PLUGIN_SUBFOLDER}")
+      set(SERVER_PLUGIN_PATH "${SERVER_PLUGIN_PATH}/${PLUGIN_SUBFOLDER}")
+  endif()
+
   if (CMAKE_SYSTEM_NAME MATCHES "Linux" OR CMAKE_GENERATOR STREQUAL "Unix Makefiles")
     set(CLIENT_PLUGIN_FULL_PATH "${CMAKE_BINARY_DIR}/interface/${CLIENT_PLUGIN_PATH}/")
     set(SERVER_PLUGIN_FULL_PATH "${CMAKE_BINARY_DIR}/assignment-client/${SERVER_PLUGIN_PATH}/")
diff --git a/interface/resources/qml/hifi/dialogs/security/Security.qml b/interface/resources/qml/hifi/dialogs/security/Security.qml
index a7a0d461a2..b1f62633e7 100644
--- a/interface/resources/qml/hifi/dialogs/security/Security.qml
+++ b/interface/resources/qml/hifi/dialogs/security/Security.qml
@@ -240,9 +240,96 @@ Rectangle {
             }
         }
 
+        // -- Plugin Permissions --
+        Item {
+            id: kpiContainer;
+            anchors.top: accountContainer.bottom;
+            anchors.left: parent.left;
+            anchors.right: parent.right;
+            height: childrenRect.height;
+
+            Rectangle {
+                id: kpiHeaderContainer;
+                anchors.top: parent.top;
+                anchors.left: parent.left;
+                anchors.right: parent.right;
+                height: 55;
+                color: hifi.colors.baseGrayHighlight;
+
+                HifiStylesUit.RalewaySemiBold {
+                    text: "Plugin Permissions";
+                    anchors.fill: parent;
+                    anchors.leftMargin: 20;
+                    color: hifi.colors.white;
+                    size: 18;
+                }
+            }
+
+            Item {
+                id: kpiScriptContainer;
+                anchors.top: kpiHeaderContainer.bottom;
+                anchors.left: parent.left;
+                anchors.right: parent.right;
+                height: 80;
+
+                HifiControlsUit.CheckBox {
+                    id: kpiScriptCheckbox;
+                    readonly property string kpiSettingsKey: "private/enableScriptingPlugins"
+                    checked: Settings.getValue(kpiSettingsKey, false);
+                    text: "Enable custom script plugins (requires restart)"
+                    // Anchors
+                    anchors.verticalCenter: parent.verticalCenter;
+                    anchors.left: parent.left;
+                    anchors.leftMargin: 20;
+                    boxSize: 24;
+                    labelFontSize: 18;
+                    colorScheme: hifi.colorSchemes.dark
+                    color: hifi.colors.white;
+                    width: 300;
+                    onCheckedChanged: Settings.setValue(kpiSettingsKey, checked);
+                }
+
+                HifiStylesUit.RalewaySemiBold {
+                    id: kpiScriptHelp;
+                    text: '[?]';
+                    // Anchors
+                    anchors.verticalCenter: parent.verticalCenter;
+                    anchors.left: kpiScriptCheckbox.right;
+                    width: 30;
+                    height: 30;
+                    // Text size
+                    size: 18;
+                    // Style
+                    color: hifi.colors.blueHighlight;
+
+                    MouseArea {
+                        anchors.fill: parent;
+                        hoverEnabled: true;
+                        onEntered: {
+                            parent.color = hifi.colors.blueAccent;
+                        }
+                        onExited: {
+                            parent.color = hifi.colors.blueHighlight;
+                        }
+                        onClicked: {
+                            lightboxPopup.titleText = "Script Plugin Infrastructure by Kasen";
+                            lightboxPopup.bodyText = "Toggles the activation of scripting plugins in the 'plugins/scripting' folder. \n\n"
+                              + "Created by https://kasen.io/";
+                            lightboxPopup.button1text = "OK";
+                            lightboxPopup.button1method = function() {
+                                lightboxPopup.visible = false;
+                            }
+                            lightboxPopup.visible = true;
+                        }
+                    }
+                }
+            }
+        }
+
+
         Item {
             id: walletContainer;
-            anchors.top: accountContainer.bottom;
+            anchors.top: kpiContainer.bottom;
             anchors.left: parent.left;
             anchors.right: parent.right;
             height: childrenRect.height;
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index b318f07d8f..b719f26c68 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -810,6 +810,7 @@ bool setupEssentials(int& argc, char** argv, bool runningMarkerExisted) {
     }
 
     // Tell the plugin manager about our statically linked plugins
+    DependencyManager::set<ScriptInitializers>();
     DependencyManager::set<PluginManager>();
     auto pluginManager = PluginManager::getInstance();
     pluginManager->setInputPluginProvider([] { return getInputPlugins(); });
@@ -859,7 +860,6 @@ bool setupEssentials(int& argc, char** argv, bool runningMarkerExisted) {
 #endif
     DependencyManager::set<StatTracker>();
     DependencyManager::set<ScriptEngines>(ScriptEngine::CLIENT_SCRIPT, defaultScriptsOverrideOption);
-    DependencyManager::set<ScriptInitializerMixin, NativeScriptInitializers>();
     DependencyManager::set<Preferences>();
     DependencyManager::set<recording::Deck>();
     DependencyManager::set<recording::Recorder>();
@@ -3425,7 +3425,7 @@ void Application::onDesktopRootContextCreated(QQmlContext* surfaceContext) {
     surfaceContext->setContextProperty("Window", DependencyManager::get<WindowScriptingInterface>().data());
     surfaceContext->setContextProperty("Desktop", DependencyManager::get<DesktopScriptingInterface>().data());
     surfaceContext->setContextProperty("MenuInterface", MenuScriptingInterface::getInstance());
-    surfaceContext->setContextProperty("Settings", SettingsScriptingInterface::getInstance());
+    surfaceContext->setContextProperty("Settings", new QMLSettingsScriptingInterface(surfaceContext));
     surfaceContext->setContextProperty("ScriptDiscoveryService", DependencyManager::get<ScriptEngines>().data());
     surfaceContext->setContextProperty("AvatarBookmarks", DependencyManager::get<AvatarBookmarks>().data());
     surfaceContext->setContextProperty("LocationBookmarks", DependencyManager::get<LocationBookmarks>().data());
@@ -3541,7 +3541,7 @@ void Application::setupQmlSurface(QQmlContext* surfaceContext, bool setAdditiona
         surfaceContext->setContextProperty("offscreenFlags", flags);
         surfaceContext->setContextProperty("AddressManager", DependencyManager::get<AddressManager>().data());
 
-        surfaceContext->setContextProperty("Settings", SettingsScriptingInterface::getInstance());
+        surfaceContext->setContextProperty("Settings", new QMLSettingsScriptingInterface(surfaceContext));
         surfaceContext->setContextProperty("MenuInterface", MenuScriptingInterface::getInstance());
         surfaceContext->setContextProperty("Performance", new PerformanceScriptingInterface());
 
diff --git a/interface/src/scripting/SettingsScriptingInterface.cpp b/interface/src/scripting/SettingsScriptingInterface.cpp
index c47d8e1da1..13eddddb1f 100644
--- a/interface/src/scripting/SettingsScriptingInterface.cpp
+++ b/interface/src/scripting/SettingsScriptingInterface.cpp
@@ -38,6 +38,14 @@ void SettingsScriptingInterface::setValue(const QString& setting, const QVariant
     if (getValue(setting) == value) {
         return;
     }
+    if (setting.startsWith("private/")) {
+        if (_restrictPrivateValues) {
+            qWarning() << "SettingsScriptingInterface::setValue -- restricted write: " << setting << value;
+            return;
+        } else {
+            qInfo() << "SettingsScriptingInterface::setValue -- allowing restricted write: " << setting << value;
+        }
+    }
     // Make a deep-copy of the string.
     // Dangling pointers can occur with QStrings that are implicitly shared from a QScriptEngine.
     QString deepCopy = QString::fromUtf16(setting.utf16());
diff --git a/interface/src/scripting/SettingsScriptingInterface.h b/interface/src/scripting/SettingsScriptingInterface.h
index ff00299fd0..f321c41e76 100644
--- a/interface/src/scripting/SettingsScriptingInterface.h
+++ b/interface/src/scripting/SettingsScriptingInterface.h
@@ -27,7 +27,6 @@
 
 class SettingsScriptingInterface : public QObject {
     Q_OBJECT
-    SettingsScriptingInterface() { };
 public:
     static SettingsScriptingInterface* getInstance();
 
@@ -67,6 +66,16 @@ public slots:
 
 signals:
     void valueChanged(const QString& setting, const QVariant& value);
+
+protected:
+    SettingsScriptingInterface(QObject* parent = nullptr) : QObject(parent) { };
+    bool _restrictPrivateValues { true };
+};
+
+class QMLSettingsScriptingInterface : public SettingsScriptingInterface {
+    Q_OBJECT
+public:
+    QMLSettingsScriptingInterface(QObject* parent) : SettingsScriptingInterface(parent) { _restrictPrivateValues = false; }
 };
 
 #endif // hifi_SettingsScriptingInterface_h
diff --git a/libraries/entities-renderer/src/EntityTreeRenderer.cpp b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
index fd82567a94..a8ef41643a 100644
--- a/libraries/entities-renderer/src/EntityTreeRenderer.cpp
+++ b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
@@ -29,7 +29,7 @@
 #include <PrioritySortUtil.h>
 #include <Rig.h>
 #include <SceneScriptingInterface.h>
-#include <ScriptEngine.h>
+#include <ScriptEngines.h>
 #include <EntitySimulation.h>
 #include <ZoneRenderer.h>
 #include <PhysicalEntitySimulation.h>
@@ -146,7 +146,7 @@ int EntityTreeRenderer::_entitiesScriptEngineCount = 0;
 void EntityTreeRenderer::resetEntitiesScriptEngine() {
     _entitiesScriptEngine = scriptEngineFactory(ScriptEngine::ENTITY_CLIENT_SCRIPT, NO_SCRIPT,
                                                 QString("about:Entities %1").arg(++_entitiesScriptEngineCount));
-    _scriptingServices->registerScriptEngineWithApplicationServices(_entitiesScriptEngine);
+    DependencyManager::get<ScriptEngines>()->runScriptInitializers(_entitiesScriptEngine);
     _entitiesScriptEngine->runInThread();
     auto entitiesScriptEngineProvider = qSharedPointerCast<EntitiesScriptEngineProvider>(_entitiesScriptEngine);
     auto entityScriptingInterface = DependencyManager::get<EntityScriptingInterface>();
diff --git a/libraries/entities/src/EntityEditFilters.cpp b/libraries/entities/src/EntityEditFilters.cpp
index a763c0f146..a222ca8216 100644
--- a/libraries/entities/src/EntityEditFilters.cpp
+++ b/libraries/entities/src/EntityEditFilters.cpp
@@ -14,6 +14,7 @@
 #include <QUrl>
 
 #include <ResourceManager.h>
+#include <shared/ScriptInitializerMixin.h>
 
 QList<EntityItemID> EntityEditFilters::getZonesByPosition(glm::vec3& position) {
     QList<EntityItemID> zones;
@@ -258,7 +259,13 @@ void EntityEditFilters::scriptRequestFinished(EntityItemID entityID) {
         if (hasCorrectSyntax(program)) {
             // create a QScriptEngine for this script
             QScriptEngine* engine = new QScriptEngine();
-            engine->evaluate(scriptContents);
+            engine->setObjectName("filter:" + entityID.toString());
+            engine->setProperty("type", "edit_filter");
+            engine->setProperty("fileName", urlString);
+            engine->setProperty("entityID", entityID);
+            engine->globalObject().setProperty("Script", engine->newQObject(engine));
+            DependencyManager::get<ScriptInitializers>()->runScriptInitializers(engine);
+            engine->evaluate(scriptContents, urlString);
             if (!hadUncaughtExceptions(*engine, urlString)) {
                 // put the engine in the engine map (so we don't leak them, etc...)
                 FilterData filterData;
diff --git a/libraries/networking/src/Assignment.cpp b/libraries/networking/src/Assignment.cpp
index 71a3cfb269..735f6dbc74 100644
--- a/libraries/networking/src/Assignment.cpp
+++ b/libraries/networking/src/Assignment.cpp
@@ -154,7 +154,7 @@ const char* Assignment::typeToString(Assignment::Type type) {
 
 QDebug operator<<(QDebug debug, const Assignment &assignment) {
     debug.nospace() << "UUID: " << qPrintable(assignment.getUUID().toString()) <<
-        ", Type: " << assignment.getType();
+        ", Type: " << assignment.getTypeName() << " (" << assignment.getType() << ")";
     
     if (!assignment.getPool().isEmpty()) {
         debug << ", Pool: " << assignment.getPool();
diff --git a/libraries/networking/src/ThreadedAssignment.cpp b/libraries/networking/src/ThreadedAssignment.cpp
index b8a8f65080..e680b22fdc 100644
--- a/libraries/networking/src/ThreadedAssignment.cpp
+++ b/libraries/networking/src/ThreadedAssignment.cpp
@@ -29,6 +29,9 @@ ThreadedAssignment::ThreadedAssignment(ReceivedMessage& message) :
     _domainServerTimer(this),
     _statsTimer(this)
 {
+    // use <mixer-type> as a temporary targetName name until commonInit can be called later
+    LogHandler::getInstance().setTargetName(QString("<%1>").arg(getTypeName()));
+
     static const int STATS_TIMEOUT_MS = 1000;
     _statsTimer.setInterval(STATS_TIMEOUT_MS); // 1s, Qt::CoarseTimer acceptable
     connect(&_statsTimer, &QTimer::timeout, this, &ThreadedAssignment::sendStatsPacket);
diff --git a/libraries/plugins/src/plugins/PluginManager.cpp b/libraries/plugins/src/plugins/PluginManager.cpp
index 0d0209e35f..8f1184904e 100644
--- a/libraries/plugins/src/plugins/PluginManager.cpp
+++ b/libraries/plugins/src/plugins/PluginManager.cpp
@@ -84,6 +84,11 @@ bool isDisabled(QJsonObject metaData) {
     return false;
 }
 
+int PluginManager::instantiate() {
+    auto loaders = getLoadedPlugins();
+    return std::count_if(loaders.begin(), loaders.end(), [](const auto& loader) { return (bool)loader->instance(); });
+}
+
  auto PluginManager::getLoadedPlugins() const -> const LoaderList& {
     static std::once_flag once;
     static LoaderList loadedPlugins;
@@ -105,6 +110,16 @@ bool isDisabled(QJsonObject metaData) {
             pluginDir.setNameFilters(QStringList() << "libplugins_lib*.so");
 #endif
             auto candidates = pluginDir.entryList();
+
+            if (_enableScriptingPlugins.get()) {
+                QDir scriptingPluginDir{ pluginDir };
+                scriptingPluginDir.cd("scripting");
+                qCDebug(plugins) << "Loading scripting plugins from " << scriptingPluginDir.path();
+                for (auto plugin : scriptingPluginDir.entryList()) {
+                    candidates << "scripting/" + plugin;
+                }
+            }
+
             for (auto plugin : candidates) {
                 qCDebug(plugins) << "Attempting plugin" << qPrintable(plugin);
                 QSharedPointer<QPluginLoader> loader(new QPluginLoader(pluginPath + plugin));
@@ -139,6 +154,8 @@ bool isDisabled(QJsonObject metaData) {
                     qCDebug(plugins) << " " << qPrintable(loader->errorString());
                 }
             }
+        } else {
+            qWarning() << "pluginPath does not exit..." << pluginDir;
         }
     });
     return loadedPlugins;
diff --git a/libraries/plugins/src/plugins/PluginManager.h b/libraries/plugins/src/plugins/PluginManager.h
index 1a578c7406..eb377a2c8e 100644
--- a/libraries/plugins/src/plugins/PluginManager.h
+++ b/libraries/plugins/src/plugins/PluginManager.h
@@ -10,6 +10,7 @@
 #include <QObject>
 
 #include <DependencyManager.h>
+#include <SettingHandle.h>
 
 #include "Forward.h"
 
@@ -38,6 +39,7 @@ public:
     void saveSettings();
     void setContainer(PluginContainer* container) { _container = container; }
 
+    int instantiate();
     void shutdown();
 
     // Application that have statically linked plugins can expose them to the plugin manager with these function
@@ -69,6 +71,9 @@ private:
     using LoaderList = QList<Loader>;
 
     const LoaderList& getLoadedPlugins() const;
+    Setting::Handle<bool> _enableScriptingPlugins {
+        "private/enableScriptingPlugins", (bool)qgetenv("enableScriptingPlugins").toInt()
+    };
 };
 
 // TODO: we should define this value in CMake, and then use CMake
diff --git a/libraries/script-engine/src/ScriptEngine.cpp b/libraries/script-engine/src/ScriptEngine.cpp
index 80036d6ad9..8337d1911a 100644
--- a/libraries/script-engine/src/ScriptEngine.cpp
+++ b/libraries/script-engine/src/ScriptEngine.cpp
@@ -237,6 +237,11 @@ ScriptEngine::ScriptEngine(Context context, const QString& scriptContents, const
     }
 }
 
+QString ScriptEngine::getTypeAsString() const {
+    auto value = QVariant::fromValue(_type).toString();
+    return value.isEmpty() ? "unknown" : value.toLower();
+}
+
 QString ScriptEngine::getContext() const {
     switch (_context) {
         case CLIENT_SCRIPT:
diff --git a/libraries/script-engine/src/ScriptEngine.h b/libraries/script-engine/src/ScriptEngine.h
index 3ffef16844..94381ede02 100644
--- a/libraries/script-engine/src/ScriptEngine.h
+++ b/libraries/script-engine/src/ScriptEngine.h
@@ -122,6 +122,8 @@ public:
 class ScriptEngine : public BaseScriptEngine, public EntitiesScriptEngineProvider {
     Q_OBJECT
     Q_PROPERTY(QString context READ getContext)
+    Q_PROPERTY(QString type READ getTypeAsString)
+    Q_PROPERTY(QString fileName MEMBER _fileNameString CONSTANT)
 public:
 
     enum Context {
@@ -138,6 +140,7 @@ public:
         AGENT,
         AVATAR
     };
+    Q_ENUM(Type)
 
     static int processLevelMaxRetries;
     ScriptEngine(Context context, const QString& scriptContents = NO_SCRIPT, const QString& fileNameString = QString("about:ScriptEngine"));
@@ -636,6 +639,7 @@ public:
 
     void setType(Type type) { _type = type; };
     Type getType() { return _type; };
+    QString getTypeAsString() const;
 
     bool isFinished() const { return _isFinished; } // used by Application and ScriptWidget
     bool isRunning() const { return _isRunning; } // used by ScriptWidget
diff --git a/libraries/script-engine/src/ScriptEngines.cpp b/libraries/script-engine/src/ScriptEngines.cpp
index 508a26302e..fd2ebe300d 100644
--- a/libraries/script-engine/src/ScriptEngines.cpp
+++ b/libraries/script-engine/src/ScriptEngines.cpp
@@ -136,24 +136,6 @@ QUrl expandScriptUrl(const QUrl& rawScriptURL) {
 
 QObject* scriptsModel();
 
-bool NativeScriptInitializers::registerNativeScriptInitializer(NativeScriptInitializer initializer) {
-    return registerScriptInitializer([initializer](ScriptEnginePointer engine) {
-        initializer(qobject_cast<QScriptEngine*>(engine.data()));
-    });
-}
-
-bool NativeScriptInitializers::registerScriptInitializer(ScriptInitializer initializer) {
-    if (auto scriptEngines = DependencyManager::get<ScriptEngines>().data()) {
-        scriptEngines->registerScriptInitializer(initializer);
-        return true;
-    }
-    return false;
-}
-
-void ScriptEngines::registerScriptInitializer(ScriptInitializer initializer) {
-    _scriptInitializers.push_back(initializer);
-}
-
 void ScriptEngines::addScriptEngine(ScriptEnginePointer engine) {
     if (!_isStopped) {
         QMutexLocker locker(&_allScriptsMutex);
@@ -590,12 +572,8 @@ void ScriptEngines::quitWhenFinished() {
 }
 
 int ScriptEngines::runScriptInitializers(ScriptEnginePointer scriptEngine) {
-    int ii=0;
-    for (auto initializer : _scriptInitializers) {
-        ii++;
-        initializer(scriptEngine);
-    }
-    return ii;
+    auto nativeCount = DependencyManager::get<ScriptInitializers>()->runScriptInitializers(scriptEngine.data());
+    return nativeCount + ScriptInitializerMixin<ScriptEnginePointer>::runScriptInitializers(scriptEngine);
 }
 
 void ScriptEngines::launchScriptEngine(ScriptEnginePointer scriptEngine) {
diff --git a/libraries/script-engine/src/ScriptEngines.h b/libraries/script-engine/src/ScriptEngines.h
index 484ccd8932..df736e101d 100644
--- a/libraries/script-engine/src/ScriptEngines.h
+++ b/libraries/script-engine/src/ScriptEngines.h
@@ -48,13 +48,8 @@ class ScriptEngine;
  *     scripts directory of the Interface installation.
  *     <em>Read-only.</em>
  */
-class NativeScriptInitializers : public ScriptInitializerMixin {
-public:
-    bool registerNativeScriptInitializer(NativeScriptInitializer initializer) override;
-    bool registerScriptInitializer(ScriptInitializer initializer) override;
-};
 
-class ScriptEngines : public QObject, public Dependency {
+class ScriptEngines : public QObject, public Dependency, public ScriptInitializerMixin<ScriptEnginePointer> {
     Q_OBJECT
 
     Q_PROPERTY(ScriptsModel* scriptsModel READ scriptsModel CONSTANT)
@@ -62,11 +57,9 @@ class ScriptEngines : public QObject, public Dependency {
     Q_PROPERTY(QString debugScriptUrl READ getDebugScriptUrl WRITE setDebugScriptUrl)
 
 public:
-    using ScriptInitializer = ScriptInitializerMixin::ScriptInitializer;
-
     ScriptEngines(ScriptEngine::Context context, const QUrl& defaultScriptsOverride = QUrl());
-    void registerScriptInitializer(ScriptInitializer initializer);
-    int runScriptInitializers(ScriptEnginePointer engine);
+    int runScriptInitializers(ScriptEnginePointer engine) override;
+
     void loadScripts();
     void saveScripts();
 
@@ -347,7 +340,6 @@ protected:
     QHash<QUrl, ScriptEnginePointer> _scriptEnginesHash;
     QSet<ScriptEnginePointer> _allKnownScriptEngines;
     QMutex _allScriptsMutex;
-    std::list<ScriptInitializer> _scriptInitializers;
     ScriptsModel _scriptsModel;
     ScriptsModelFilter _scriptsModelFilter;
     std::atomic<bool> _isStopped { false };
diff --git a/libraries/shared/src/shared/ScriptInitializerMixin.h b/libraries/shared/src/shared/ScriptInitializerMixin.h
index 50de553b0b..cefa33c2d3 100644
--- a/libraries/shared/src/shared/ScriptInitializerMixin.h
+++ b/libraries/shared/src/shared/ScriptInitializerMixin.h
@@ -9,30 +9,38 @@
 #pragma once
 
 #include <functional>
+#include <mutex>
 #include <QSharedPointer>
 #include "../DependencyManager.h"
 
 class QScriptEngine;
 class ScriptEngine;
 
-class ScriptInitializerMixin : public QObject, public Dependency {
-    Q_OBJECT
+template <typename T> class ScriptInitializerMixin {
+public:
+    using ScriptInitializer = std::function<void(T)>;
+    virtual void registerScriptInitializer(ScriptInitializer initializer) {
+        InitializerLock lock(_scriptInitializerMutex);
+        _scriptInitializers.push_back(initializer);
+    }
+    virtual int runScriptInitializers(T engine) {
+        InitializerLock lock(_scriptInitializerMutex);
+        return std::count_if(_scriptInitializers.begin(), _scriptInitializers.end(),
+            [engine](auto initializer){ initializer(engine); return true; }
+        );
+    }
+    virtual ~ScriptInitializerMixin() {}
+protected:
+    std::mutex _scriptInitializerMutex;
+    using InitializerLock = std::lock_guard<std::mutex>;
+    std::list<ScriptInitializer> _scriptInitializers;
+};
+
+class ScriptInitializers : public ScriptInitializerMixin<QScriptEngine*>, public Dependency {
 public:
     // Lightweight `QScriptEngine*` initializer (only depends on built-in Qt components)
     // example registration:
-    // eg: [&](QScriptEngine* engine) -> bool {
+    // eg: [&](QScriptEngine* engine) {
     //     engine->globalObject().setProperties("API", engine->newQObject(...instance...))
-    //     return true;
-    // }
-    using NativeScriptInitializer = std::function<void(QScriptEngine*)>;
-    virtual bool registerNativeScriptInitializer(NativeScriptInitializer initializer) = 0;
-
-    // Heavyweight `ScriptEngine*` initializer (tightly coupled to Interface and script-engine library internals)
-    // eg: [&](ScriptEnginePointer scriptEngine) -> bool {
-    //     engine->registerGlobalObject("API", ...instance..);
-    //     return true;
-    // }
-    using ScriptEnginePointer = QSharedPointer<ScriptEngine>;
-    using ScriptInitializer = std::function<void(ScriptEnginePointer)>;
-    virtual bool registerScriptInitializer(ScriptInitializer initializer) { return false; };
+    // };
 };
diff --git a/plugins/CMakeLists.txt b/plugins/CMakeLists.txt
index 4a0f52e272..1150e27cac 100644
--- a/plugins/CMakeLists.txt
+++ b/plugins/CMakeLists.txt
@@ -43,3 +43,7 @@ set(DIR "pcmCodec")
 add_subdirectory(${DIR})
 set(DIR "hifiCodec")
 add_subdirectory(${DIR})
+
+# example plugins
+set(DIR "KasenAPIExample")
+add_subdirectory(${DIR})
diff --git a/plugins/KasenAPIExample/CMakeLists.txt b/plugins/KasenAPIExample/CMakeLists.txt
new file mode 100644
index 0000000000..96ac84e10d
--- /dev/null
+++ b/plugins/KasenAPIExample/CMakeLists.txt
@@ -0,0 +1,3 @@
+set(TARGET_NAME KasenAPIExample)
+setup_hifi_client_server_plugin(scripting)
+link_hifi_libraries(shared plugins avatars networking graphics gpu)
diff --git a/plugins/KasenAPIExample/src/ExampleScriptPlugin.h b/plugins/KasenAPIExample/src/ExampleScriptPlugin.h
new file mode 100644
index 0000000000..a6af105e0e
--- /dev/null
+++ b/plugins/KasenAPIExample/src/ExampleScriptPlugin.h
@@ -0,0 +1,56 @@
+//
+//  ExampleScriptPlugin.h
+//  plugins/KasenAPIExample/src
+//
+//  Created by Kasen IO on 2019.07.14 | realities.dev | kasenvr@gmail.com
+//  Copyright 2019 Kasen IO
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+// Supporting file containing all QtScript specific integration.
+
+#ifndef EXAMPLE_SCRIPT_PLUGIN_H
+#define EXAMPLE_SCRIPT_PLUGIN_H
+
+#if DEV_BUILD
+#pragma message("QtScript is deprecated see: doc.qt.io/qt-5/topics-scripting.html")
+#endif
+#include <QtScript/QScriptEngine>
+
+#include <QtCore/QLoggingCategory>
+#include <QCoreApplication>
+#include <shared/ScriptInitializerMixin.h>
+
+namespace example {
+
+extern const QLoggingCategory& logger;
+
+inline void setGlobalInstance(QScriptEngine* engine, const QString& name, QObject* object) {
+    auto value = engine->newQObject(object, QScriptEngine::QtOwnership);
+    engine->globalObject().setProperty(name, value);
+    qCDebug(logger) << "setGlobalInstance" << name << engine->property("fileName");
+}
+
+class ScriptPlugin : public QObject {
+    Q_OBJECT
+    QString _version;
+    Q_PROPERTY(QString version MEMBER _version CONSTANT)
+protected:
+    inline ScriptPlugin(const QString& name, const QString& version) : _version(version) {
+        setObjectName(name);
+        if (!DependencyManager::get<ScriptInitializers>()) {
+            qCWarning(logger) << "COULD NOT INITIALIZE (ScriptInitializers unavailable)" << qApp << this;
+            return;
+        }
+        qCWarning(logger) << "registering w/ScriptInitializerMixin..." << DependencyManager::get<ScriptInitializers>().data();
+        DependencyManager::get<ScriptInitializers>()->registerScriptInitializer(
+            [this](QScriptEngine* engine) { setGlobalInstance(engine, objectName(), this); });
+    }
+public slots:
+    inline QString toString() const { return QString("[%1 version=%2]").arg(objectName()).arg(_version); }
+};
+
+}  // namespace example
+
+#endif
\ No newline at end of file
diff --git a/plugins/KasenAPIExample/src/KasenAPIExample.cpp b/plugins/KasenAPIExample/src/KasenAPIExample.cpp
new file mode 100644
index 0000000000..d566d11376
--- /dev/null
+++ b/plugins/KasenAPIExample/src/KasenAPIExample.cpp
@@ -0,0 +1,139 @@
+//
+//  KasenAPIExample.cpp
+//  plugins/KasenAPIExample/src
+//
+//  Created by Kasen IO on 2019.07.14 | realities.dev | kasenvr@gmail.com
+//  Copyright 2019 Kasen IO
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+// Example of prototyping new JS APIs by leveraging the existing plugin system.
+
+#include "ExampleScriptPlugin.h"
+
+#include <QCoreApplication>
+#include <QtCore/QJsonObject>
+#include <QtCore/QLoggingCategory>
+#include <QtCore/QThread>
+#include <QtCore/QTimer>
+
+#include <SharedUtil.h>
+#include <AvatarHashMap.h>
+
+namespace custom_api_example {
+
+QLoggingCategory logger{ "custom_api_example" };
+
+class KasenAPIExample : public example::ScriptPlugin {
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "KasenAPIExample" FILE "plugin.json")
+public:
+    KasenAPIExample() : example::ScriptPlugin("KasenAPIExample", "0.0.1") {
+        qCInfo(logger) << "plugin loaded" << qApp << toString() << QThread::currentThread(); 
+    }
+
+public slots:
+    /**jsdoc
+     * Returns current microseconds (usecs) since Epoch. note: 1000usecs == 1ms
+     * @example <caption>Measure current setTimeout accuracy.</caption>
+     * var expected = 1000;
+     * var start = KasenAPIExample.now();
+     * Script.setTimeout(function () {
+     *     var elapsed = (KasenAPIExample.now() - start)/1000;
+     *     print("expected (ms):", expected, "actual (ms):", elapsed);
+     * }, expected);
+     */
+    QVariant now() const {
+        return usecTimestampNow();
+    }
+
+    /**jsdoc
+     * Returns the available blendshape names for an avatar.
+     * @example <caption>Get blendshape names</caption>
+     * print(JSON.stringify(KasenAPIExample.getBlendshapeNames(MyAvatar.sessionUUID)));
+     */
+    QStringList getBlendshapeNames(const QUuid& avatarID) const {
+        QVector<QString> out;
+        if (auto head = getAvatarHead(avatarID)) {
+            for (const auto& kv : head->getBlendshapeMap().toStdMap()) {
+                if (kv.second >= out.size()) out.resize(kv.second+1);
+                out[kv.second] = kv.first;
+            }
+        }
+        return out.toList();
+    }
+
+    /**jsdoc
+     * Returns a key-value object with active (non-zero) blendshapes.
+     * eg: { JawOpen: 1.0, ... }
+     * @example <caption>Get active blendshape map</caption>
+     * print(JSON.stringify(KasenAPIExample.getActiveBlendshapes(MyAvatar.sessionUUID)));
+     */
+    QVariant getActiveBlendshapes(const QUuid& avatarID) const {
+        if (auto head = getAvatarHead(avatarID)) {
+            return head->toJson()["blendShapes"].toVariant();
+        }
+        return {};
+    }
+
+    QVariant getBlendshapeMapping(const QUuid& avatarID) const {
+        QVariantMap out;
+        if (auto head = getAvatarHead(avatarID)) {
+            for (const auto& kv : head->getBlendshapeMap().toStdMap()) {
+                out[kv.first] = kv.second;
+            }
+        }
+        return out;
+    }
+
+    QVariant getBlendshapes(const QUuid& avatarID) const {
+        QVariantMap result;
+        if (auto head = getAvatarHead(avatarID)) {
+            QStringList names = getBlendshapeNames(avatarID);
+            auto states = head->getBlendshapeStates();
+            result = {
+                { "base", zipNonZeroValues(names, states.base) },
+                { "summed", zipNonZeroValues(names, states.summed) },
+                { "transient", zipNonZeroValues(names, states.transient) },
+            };
+        }
+        return result;
+    }
+
+private:
+    static QVariantMap zipNonZeroValues(const QStringList& keys, const QVector<float>& values) {
+        QVariantMap out;
+        for (int i=1; i < values.size(); i++) {
+            if (fabs(values[i]) > 1.0e-6) {
+                out[keys.value(i)] = values[i];
+            }
+        }
+        return out;
+    }
+    struct _HeadHelper : public HeadData {
+        QMap<QString,int> getBlendshapeMap() const {
+            return _blendshapeLookupMap;
+        }
+        struct States { QVector<float> base, summed, transient; };
+        States getBlendshapeStates() const {
+            return {
+                _blendshapeCoefficients,
+                _summedBlendshapeCoefficients,
+                _transientBlendshapeCoefficients
+            };
+        }
+    };
+    static const _HeadHelper* getAvatarHead(const QUuid& avatarID) {
+        auto avatars = DependencyManager::get<AvatarHashMap>();
+        auto avatar = avatars ? avatars->getAvatarBySessionID(avatarID) : nullptr;
+        auto head = avatar ? avatar->getHeadData() : nullptr;
+        return reinterpret_cast<const _HeadHelper*>(head);
+    }
+};
+
+}
+
+const QLoggingCategory& example::logger{ custom_api_example::logger };
+
+#include "KasenAPIExample.moc"
diff --git a/plugins/KasenAPIExample/src/plugin.json b/plugins/KasenAPIExample/src/plugin.json
new file mode 100644
index 0000000000..3e6931deec
--- /dev/null
+++ b/plugins/KasenAPIExample/src/plugin.json
@@ -0,0 +1,21 @@
+{
+    "name":"Kasen JS API Example",
+    "version": 1,
+    "package": {
+        "author": "Revofire",
+        "homepage": "www.realities.dev",
+        "version": "0.0.1",
+        "engines": {
+          "hifi-interface": ">= 0.83.0",
+          "hifi-assignment-client": ">= 0.83.0"
+        },
+        "config": {
+            "client": true,
+            "entity_client": true,
+            "entity_server": true,
+            "edit_filter": true,
+            "agent": true,
+            "avatar": true
+        }
+    }
+}