diff --git a/libnymea/integrations/pluginmetadata.cpp b/libnymea/integrations/pluginmetadata.cpp
index cd71154c..10390c4d 100644
--- a/libnymea/integrations/pluginmetadata.cpp
+++ b/libnymea/integrations/pluginmetadata.cpp
@@ -634,29 +634,29 @@ void PluginMetadata::parse(const QJsonObject &jsonObject)
                 ActionTypes actionTypes(thingClass.actionTypes());
                 EventTypes eventTypes(thingClass.eventTypes());
 
-                foreach (const StateType &ifaceStateType, iface.stateTypes()) {
+                foreach (const InterfaceStateType &ifaceStateType, iface.stateTypes()) {
                     StateType stateType = stateTypes.findByName(ifaceStateType.name());
                     if (stateType.id().isNull()) {
-                        m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement state \"" + ifaceStateType.name() + "\"");
-                        hasError = true;
-                        continue;
+                        if (!ifaceStateType.optional()) {
+                            m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement state \"" + ifaceStateType.name() + "\"");
+                            hasError = true;
+                        } else {
+                            continue;
+                        }
                     }
                     if (ifaceStateType.type() != stateType.type()) {
                         m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has not matching type: \"" + QVariant::typeToName(stateType.type()) + "\" != \"" + QVariant::typeToName(ifaceStateType.type()) + "\"");
                         hasError = true;
-                        continue;
                     }
                     if (ifaceStateType.minValue().isValid() && !ifaceStateType.minValue().isNull()) {
                         if (ifaceStateType.minValue().toString() == "any") {
                             if (stateType.minValue().isNull()) {
                                 m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has no minimum value defined.");
                                 hasError = true;
-                                continue;
                             }
                         } else if (ifaceStateType.minValue() != stateType.minValue()) {
                             m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has not matching minimum value: \"" + ifaceStateType.minValue().toString() + "\" != \"" + stateType.minValue().toString() + "\"");
                             hasError = true;
-                            continue;
                         }
                     }
                     if (ifaceStateType.maxValue().isValid() && !ifaceStateType.maxValue().isNull()) {
@@ -664,32 +664,32 @@ void PluginMetadata::parse(const QJsonObject &jsonObject)
                             if (stateType.maxValue().isNull()) {
                                 m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has no maximum value defined.");
                                 hasError = true;
-                                continue;
                             }
                         } else if (ifaceStateType.maxValue() != stateType.maxValue()) {
                             m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has not matching maximum value: \"" + ifaceStateType.maxValue().toString() + "\" != \"" + stateType.minValue().toString() + "\"");
                             hasError = true;
-                            continue;
                         }
                     }
                     if (!ifaceStateType.possibleValues().isEmpty() && ifaceStateType.possibleValues() != stateType.possibleValues()) {
                         m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has not matching allowed values.");
                         hasError = true;
-                        continue;
                     }
                     if (ifaceStateType.unit() != Types::UnitNone && ifaceStateType.unit() != stateType.unit()) {
                         QMetaEnum unitEnum = QMetaEnum::fromType<Types::Unit>();
                         m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but state \"" + stateType.name() + "\" has not matching unit: \"" + unitEnum.valueToKey(ifaceStateType.unit()) + "\" != \"" + unitEnum.valueToKey(stateType.unit()));
                         hasError = true;
-                        continue;
                     }
                 }
 
-                foreach (const ActionType &ifaceActionType, iface.actionTypes()) {
+                foreach (const InterfaceActionType &ifaceActionType, iface.actionTypes()) {
                     ActionType actionType = actionTypes.findByName(ifaceActionType.name());
                     if (actionType.id().isNull()) {
-                        m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement action \"" + ifaceActionType.name() + "\"");
-                        hasError = true;
+                        if (!ifaceActionType.optional()) {
+                            m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement action \"" + ifaceActionType.name() + "\"");
+                            hasError = true;
+                        } else {
+                            continue;
+                        }
                     }
                     foreach (const ParamType &ifaceActionParamType, ifaceActionType.paramTypes()) {
                         ParamType paramType = actionType.paramTypes().findByName(ifaceActionParamType.name());
@@ -711,11 +711,15 @@ void PluginMetadata::parse(const QJsonObject &jsonObject)
                     }
                 }
 
-                foreach (const EventType &ifaceEventType, iface.eventTypes()) {
+                foreach (const InterfaceEventType &ifaceEventType, iface.eventTypes()) {
                     EventType eventType = eventTypes.findByName(ifaceEventType.name());
                     if (!eventType.isValid()) {
-                        m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement event \"" + ifaceEventType.name() + "\"");
-                        hasError = true;
+                        if (!ifaceEventType.optional()) {
+                            m_validationErrors.append("Thing class \"" + thingClass.name() + "\" claims to implement interface \"" + value.toString() + "\" but doesn't implement event \"" + ifaceEventType.name() + "\"");
+                            hasError = true;
+                        } else {
+                            continue;
+                        }
                     }
                     foreach (const ParamType &ifaceEventParamType, ifaceEventType.paramTypes()) {
                         ParamType paramType = eventType.paramTypes().findByName(ifaceEventParamType.name());
diff --git a/libnymea/integrations/thingutils.cpp b/libnymea/integrations/thingutils.cpp
index 8a1c97bb..7d47ac82 100644
--- a/libnymea/integrations/thingutils.cpp
+++ b/libnymea/integrations/thingutils.cpp
@@ -189,16 +189,17 @@ Interface ThingUtils::loadInterface(const QString &name)
         }
     }
 
-    StateTypes stateTypes;
-    ActionTypes actionTypes;
-    EventTypes eventTypes;
+    InterfaceStateTypes stateTypes;
+    InterfaceActionTypes actionTypes;
+    InterfaceEventTypes eventTypes;
     foreach (const QVariant &stateVariant, content.value("states").toList()) {
-        StateType stateType;
+        InterfaceStateType stateType;
         stateType.setName(stateVariant.toMap().value("name").toString());
         stateType.setType(QVariant::nameToType(stateVariant.toMap().value("type").toByteArray()));
         stateType.setPossibleValues(stateVariant.toMap().value("allowedValues").toList());
         stateType.setMinValue(stateVariant.toMap().value("minValue"));
         stateType.setMaxValue(stateVariant.toMap().value("maxValue"));
+        stateType.setOptional(stateVariant.toMap().value("optional", false).toBool());
         if (stateVariant.toMap().contains("unit")) {
             QMetaEnum unitEnum = QMetaEnum::fromType<Types::Unit>();
             int enumValue = unitEnum.keyToValue("Unit" + stateVariant.toMap().value("unit").toByteArray());
@@ -210,8 +211,9 @@ Interface ThingUtils::loadInterface(const QString &name)
         }
         stateTypes.append(stateType);
 
-        EventType stateChangeEventType;
+        InterfaceEventType stateChangeEventType;
         stateChangeEventType.setName(stateType.name());
+        stateChangeEventType.setOptional(stateType.optional());
         ParamType stateChangeEventParamType;
         stateChangeEventParamType.setName(stateType.name());
         stateChangeEventParamType.setType(stateType.type());
@@ -222,16 +224,18 @@ Interface ThingUtils::loadInterface(const QString &name)
         eventTypes.append(stateChangeEventType);
 
         if (stateVariant.toMap().value("writable", false).toBool()) {
-            ActionType stateChangeActionType;
+            InterfaceActionType stateChangeActionType;
             stateChangeActionType.setName(stateType.name());
+            stateChangeActionType.setOptional(stateType.optional());
             stateChangeActionType.setParamTypes(ParamTypes() << stateChangeEventParamType);
             actionTypes.append(stateChangeActionType);
         }
     }
 
     foreach (const QVariant &actionVariant, content.value("actions").toList()) {
-        ActionType actionType;
+        InterfaceActionType actionType;
         actionType.setName(actionVariant.toMap().value("name").toString());
+        actionType.setOptional(actionVariant.toMap().value("optional").toBool());
         ParamTypes paramTypes;
         foreach (const QVariant &actionParamVariant, actionVariant.toMap().value("params").toList()) {
             ParamType paramType;
@@ -246,8 +250,9 @@ Interface ThingUtils::loadInterface(const QString &name)
     }
 
     foreach (const QVariant &eventVariant, content.value("events").toList()) {
-        EventType eventType;
+        InterfaceEventType eventType;
         eventType.setName(eventVariant.toMap().value("name").toString());
+        eventType.setOptional(eventVariant.toMap().value("optional").toBool());
         ParamTypes paramTypes;
         foreach (const QVariant &eventParamVariant, eventVariant.toMap().value("params").toList()) {
             ParamType paramType;
@@ -267,20 +272,20 @@ Interface ThingUtils::loadInterface(const QString &name)
 
 Interface ThingUtils::mergeInterfaces(const Interface &iface1, const Interface &iface2)
 {
-    EventTypes eventTypes = iface1.eventTypes();
-    foreach (const EventType &et, iface2.eventTypes()) {
+    InterfaceEventTypes eventTypes = iface1.eventTypes();
+    foreach (const InterfaceEventType &et, iface2.eventTypes()) {
         if (eventTypes.findByName(et.name()).name().isEmpty()) {
             eventTypes.append(et);
         }
     }
-    StateTypes stateTypes = iface1.stateTypes();
-    foreach (const StateType &st, iface2.stateTypes()) {
+    InterfaceStateTypes stateTypes = iface1.stateTypes();
+    foreach (const InterfaceStateType &st, iface2.stateTypes()) {
         if (stateTypes.findByName(st.name()).name().isEmpty()) {
             stateTypes.append(st);
         }
     }
-    ActionTypes actionTypes = iface1.actionTypes();
-    foreach (const ActionType &at, iface2.actionTypes()) {
+    InterfaceActionTypes actionTypes = iface1.actionTypes();
+    foreach (const InterfaceActionType &at, iface2.actionTypes()) {
         if (actionTypes.findByName(at.name()).name().isEmpty()) {
             actionTypes.append(at);
         }
diff --git a/libnymea/libnymea.pro b/libnymea/libnymea.pro
index 76ff4cda..2da85aad 100644
--- a/libnymea/libnymea.pro
+++ b/libnymea/libnymea.pro
@@ -35,6 +35,9 @@ HEADERS += \
     types/browseritem.h \
     types/browseritemaction.h \
     types/browseraction.h \
+    types/interfaceactiontype.h \
+    types/interfaceeventtype.h \
+    types/interfacestatetype.h \
     types/mediabrowseritem.h \
     types/thingclass.h \
     typeutils.h \
@@ -149,6 +152,9 @@ SOURCES += \
     types/browseritem.cpp \
     types/browseritemaction.cpp \
     types/browseraction.cpp \
+    types/interfaceactiontype.cpp \
+    types/interfaceeventtype.cpp \
+    types/interfacestatetype.cpp \
     types/mediabrowseritem.cpp \
     types/action.cpp \
     types/actiontype.cpp \
diff --git a/libnymea/types/interface.cpp b/libnymea/types/interface.cpp
index dd73f3ce..83d72e75 100644
--- a/libnymea/types/interface.cpp
+++ b/libnymea/types/interface.cpp
@@ -30,7 +30,7 @@
 
 #include "interface.h"
 
-Interface::Interface(const QString &name, const ActionTypes &actionTypes, const EventTypes &eventTypes, const StateTypes &stateTypes):
+Interface::Interface(const QString &name, const InterfaceActionTypes &actionTypes, const InterfaceEventTypes &eventTypes, const InterfaceStateTypes &stateTypes):
     m_name(name),
     m_actionTypes(actionTypes),
     m_eventTypes(eventTypes),
@@ -44,17 +44,17 @@ QString Interface::name() const
     return m_name;
 }
 
-ActionTypes Interface::actionTypes() const
+InterfaceActionTypes Interface::actionTypes() const
 {
     return m_actionTypes;
 }
 
-EventTypes Interface::eventTypes() const
+InterfaceEventTypes Interface::eventTypes() const
 {
     return m_eventTypes;
 }
 
-StateTypes Interface::stateTypes() const
+InterfaceStateTypes Interface::stateTypes() const
 {
     return m_stateTypes;
 }
diff --git a/libnymea/types/interface.h b/libnymea/types/interface.h
index a9c6d834..e4164483 100644
--- a/libnymea/types/interface.h
+++ b/libnymea/types/interface.h
@@ -31,28 +31,29 @@
 #ifndef INTERFACE_H
 #define INTERFACE_H
 
-#include "eventtype.h"
-#include "actiontype.h"
-#include "statetype.h"
+#include "interfaceeventtype.h"
+#include "interfaceactiontype.h"
+#include "interfacestatetype.h"
 
 class Interface{
 public:
     Interface() = default;
-    Interface(const QString &name, const ActionTypes &actionTypes, const EventTypes &eventTypes, const StateTypes &stateTypes);
+    Interface(const QString &name, const InterfaceActionTypes &actionTypes, const InterfaceEventTypes &eventTypes, const InterfaceStateTypes &stateTypes);
 
     QString name() const;
 
-    ActionTypes actionTypes() const;
-    EventTypes eventTypes() const;
-    StateTypes stateTypes() const;
+    InterfaceActionTypes actionTypes() const;
+    InterfaceEventTypes eventTypes() const;
+    InterfaceStateTypes stateTypes() const;
 
     bool isValid() const;
 private:
     QUuid m_id;
     QString m_name;
-    ActionTypes m_actionTypes;
-    EventTypes m_eventTypes;
-    StateTypes m_stateTypes;
+    InterfaceActionTypes m_actionTypes;
+    InterfaceEventTypes m_eventTypes;
+    InterfaceStateTypes m_stateTypes;
+    bool m_optional = false;
 };
 
 class LIBNYMEA_EXPORT Interfaces: public QList<Interface>
diff --git a/libnymea/types/interfaceactiontype.cpp b/libnymea/types/interfaceactiontype.cpp
new file mode 100644
index 00000000..ef66d56e
--- /dev/null
+++ b/libnymea/types/interfaceactiontype.cpp
@@ -0,0 +1,32 @@
+#include "interfaceactiontype.h"
+
+InterfaceActionType::InterfaceActionType()
+{
+
+}
+
+bool InterfaceActionType::optional() const
+{
+    return m_optional;
+}
+
+void InterfaceActionType::setOptional(bool optional)
+{
+    m_optional = optional;
+}
+
+InterfaceActionTypes::InterfaceActionTypes(const QList<InterfaceActionType> &other):
+    QList<InterfaceActionType>(other)
+{
+
+}
+
+InterfaceActionType InterfaceActionTypes::findByName(const QString &name)
+{
+    foreach (const InterfaceActionType &iat, *this) {
+        if (iat.name() == name) {
+            return iat;
+        }
+    }
+    return InterfaceActionType();
+}
diff --git a/libnymea/types/interfaceactiontype.h b/libnymea/types/interfaceactiontype.h
new file mode 100644
index 00000000..1e650722
--- /dev/null
+++ b/libnymea/types/interfaceactiontype.h
@@ -0,0 +1,26 @@
+#ifndef INTERFACEACTIONTYPE_H
+#define INTERFACEACTIONTYPE_H
+
+#include "actiontype.h"
+
+class InterfaceActionType: public ActionType
+{
+public:
+    InterfaceActionType();
+
+    bool optional() const;
+    void setOptional(bool optional);
+
+private:
+    bool m_optional = false;
+};
+
+class InterfaceActionTypes: public QList<InterfaceActionType>
+{
+public:
+    InterfaceActionTypes() = default;
+    InterfaceActionTypes(const QList<InterfaceActionType> &other);
+    InterfaceActionType findByName(const QString &name);
+};
+
+#endif // INTERFACEACTIONTYPE_H
diff --git a/libnymea/types/interfaceeventtype.cpp b/libnymea/types/interfaceeventtype.cpp
new file mode 100644
index 00000000..1ee3f9ac
--- /dev/null
+++ b/libnymea/types/interfaceeventtype.cpp
@@ -0,0 +1,32 @@
+#include "interfaceeventtype.h"
+
+InterfaceEventType::InterfaceEventType()
+{
+
+}
+
+bool InterfaceEventType::optional() const
+{
+    return m_optional;
+}
+
+void InterfaceEventType::setOptional(bool optional)
+{
+    m_optional = optional;
+}
+
+InterfaceEventTypes::InterfaceEventTypes(const QList<InterfaceEventType> &other):
+    QList<InterfaceEventType>(other)
+{
+
+}
+
+InterfaceEventType InterfaceEventTypes::findByName(const QString &name)
+{
+    foreach (const InterfaceEventType &iet, *this) {
+        if (iet.name() == name) {
+            return iet;
+        }
+    }
+    return InterfaceEventType();
+}
diff --git a/libnymea/types/interfaceeventtype.h b/libnymea/types/interfaceeventtype.h
new file mode 100644
index 00000000..c81305b4
--- /dev/null
+++ b/libnymea/types/interfaceeventtype.h
@@ -0,0 +1,26 @@
+#ifndef INTERFACEEVENTTYPE_H
+#define INTERFACEEVENTTYPE_H
+
+#include "eventtype.h"
+
+class InterfaceEventType: public EventType
+{
+public:
+    InterfaceEventType();
+
+    bool optional() const;
+    void setOptional(bool optional);
+
+private:
+    bool m_optional = false;
+};
+
+class InterfaceEventTypes: public QList<InterfaceEventType>
+{
+public:
+    InterfaceEventTypes() = default;
+    InterfaceEventTypes(const QList<InterfaceEventType> &other);
+    InterfaceEventType findByName(const QString &name);
+};
+
+#endif // INTERFACEEVENTTYPE_H
diff --git a/libnymea/types/interfacestatetype.cpp b/libnymea/types/interfacestatetype.cpp
new file mode 100644
index 00000000..97981bd1
--- /dev/null
+++ b/libnymea/types/interfacestatetype.cpp
@@ -0,0 +1,32 @@
+#include "interfacestatetype.h"
+
+InterfaceStateType::InterfaceStateType()
+{
+
+}
+
+bool InterfaceStateType::optional() const
+{
+    return m_optional;
+}
+
+void InterfaceStateType::setOptional(bool optional)
+{
+    m_optional = optional;
+}
+
+InterfaceStateTypes::InterfaceStateTypes(const QList<InterfaceStateType> &other):
+    QList<InterfaceStateType>(other)
+{
+
+}
+
+InterfaceStateType InterfaceStateTypes::findByName(const QString &name)
+{
+    foreach (const InterfaceStateType &ist, *this) {
+        if (ist.name() == name) {
+            return ist;
+        }
+    }
+    return InterfaceStateType();
+}
diff --git a/libnymea/types/interfacestatetype.h b/libnymea/types/interfacestatetype.h
new file mode 100644
index 00000000..247f3b48
--- /dev/null
+++ b/libnymea/types/interfacestatetype.h
@@ -0,0 +1,26 @@
+#ifndef INTERFACESTATETYPE_H
+#define INTERFACESTATETYPE_H
+
+#include "statetype.h"
+
+class InterfaceStateType: public StateType
+{
+public:
+    InterfaceStateType();
+
+    bool optional() const;
+    void setOptional(bool optional);
+
+private:
+    bool m_optional = false;
+};
+
+class InterfaceStateTypes: public QList<InterfaceStateType>
+{
+public:
+    InterfaceStateTypes() = default;
+    InterfaceStateTypes(const QList<InterfaceStateType> &other);
+    InterfaceStateType findByName(const QString &name);
+};
+
+#endif // INTERFACESTATETYPE_H