diff --git a/frontend/src/app/plugins/api.cljs b/frontend/src/app/plugins/api.cljs
index c43191eda..adf18684a 100644
--- a/frontend/src/app/plugins/api.cljs
+++ b/frontend/src/app/plugins/api.cljs
@@ -26,7 +26,7 @@
    [app.plugins.page :as page]
    [app.plugins.shape :as shape]
    [app.plugins.user :as user]
-   [app.plugins.utils :as utils]
+   [app.plugins.utils :as u]
    [app.plugins.viewport :as viewport]
    [app.util.object :as obj]
    [beicon.v2.core :as rx]
@@ -61,7 +61,7 @@
 
   (getViewport
     [_]
-    (viewport/create-proxy $plugin))
+    (viewport/viewport-proxy $plugin))
 
   (getFile
     [_]
@@ -108,28 +108,50 @@
 
   (uploadMediaUrl
     [_ name url]
-    (let [file-id (:current-file-id @st/state)]
-      (p/create
-       (fn [resolve reject]
-         (->> (dwm/upload-media-url name file-id url)
-              (rx/map utils/to-js)
-              (rx/take 1)
-              (rx/subs! resolve reject))))))
+    (cond
+      (not (string? name))
+      (u/display-not-valid :uploadMedia-name name)
+
+      (not (string? url))
+      (u/display-not-valid :uploadMedia-url url)
+
+      :else
+      (let [file-id (:current-file-id @st/state)]
+        (p/create
+         (fn [resolve reject]
+           (->> (dwm/upload-media-url name file-id url)
+                (rx/map u/to-js)
+                (rx/take 1)
+                (rx/subs! resolve reject)))))))
 
   (group
     [_ shapes]
-    (let [file-id (:current-file-id @st/state)
-          page-id (:current-page-id @st/state)
-          id (uuid/next)
-          ids (into #{} (map #(obj/get % "$id")) shapes)]
-      (st/emit! (dwg/group-shapes id ids))
-      (shape/shape-proxy $plugin file-id page-id id)))
+    (cond
+      (or (not (array? shapes)) (not (every? shape/shape-proxy? shapes)))
+      (u/display-not-valid :group-shapes shapes)
+
+      :else
+      (let [file-id (:current-file-id @st/state)
+            page-id (:current-page-id @st/state)
+            id (uuid/next)
+            ids (into #{} (map #(obj/get % "$id")) shapes)]
+        (st/emit! (dwg/group-shapes id ids))
+        (shape/shape-proxy $plugin file-id page-id id))))
 
   (ungroup
     [_ group & rest]
-    (let [shapes (concat [group] rest)
-          ids (into #{} (map #(obj/get % "$id")) shapes)]
-      (st/emit! (dwg/ungroup-shapes ids))))
+
+    (cond
+      (not (shape/shape-proxy? group))
+      (u/display-not-valid :ungroup group)
+
+      (and (some? rest) (not (every? shape/shape-proxy? rest)))
+      (u/display-not-valid :ungroup rest)
+
+      :else
+      (let [shapes (concat [group] rest)
+            ids (into #{} (map #(obj/get % "$id")) shapes)]
+        (st/emit! (dwg/ungroup-shapes ids)))))
 
   (createFrame
     [_]
@@ -161,23 +183,32 @@
 
   (createText
     [_ text]
-    (let [file-id (:current-file-id @st/state)
-          page-id (:current-page-id @st/state)
-          page (dm/get-in @st/state [:workspace-data :pages-index page-id])
-          shape (-> (cts/setup-shape {:type :text :x 0 :y 0 :grow-type :auto-width})
-                    (txt/change-text text)
-                    (assoc :position-data nil))
-          changes
-          (-> (cb/empty-changes)
-              (cb/with-page page)
-              (cb/with-objects (:objects page))
-              (cb/add-object shape))]
-      (st/emit! (ch/commit-changes changes))
-      (shape/shape-proxy $plugin file-id page-id (:id shape))))
+    (cond
+      (or (not (string? text)) (empty? text))
+      (u/display-not-valid :createText text)
+
+      :else
+      (let [file-id (:current-file-id @st/state)
+            page-id (:current-page-id @st/state)
+            page (dm/get-in @st/state [:workspace-data :pages-index page-id])
+            shape (-> (cts/setup-shape {:type :text :x 0 :y 0 :grow-type :auto-width})
+                      (txt/change-text text)
+                      (assoc :position-data nil))
+            changes
+            (-> (cb/empty-changes)
+                (cb/with-page page)
+                (cb/with-objects (:objects page))
+                (cb/add-object shape))]
+        (st/emit! (ch/commit-changes changes))
+        (shape/shape-proxy $plugin file-id page-id (:id shape)))))
 
   (createShapeFromSvg
     [_ svg-string]
-    (when (some? svg-string)
+    (cond
+      (not (string? svg-string))
+      (u/display-not-valid :createShapeFromSvg svg-string)
+
+      :else
       (let [id (uuid/next)
             file-id (:current-file-id @st/state)
             page-id (:current-page-id @st/state)]
@@ -185,15 +216,19 @@
         (shape/shape-proxy $plugin file-id page-id id))))
 
   (createBoolean [_ bool-type shapes]
-    (let [ids (into #{} (map #(obj/get % "$id")) shapes)
-          bool-type (keyword bool-type)]
+    (let [bool-type (keyword bool-type)]
+      (cond
+        (not (contains? cts/bool-types bool-type))
+        (u/display-not-valid :createBoolean-boolType bool-type)
 
-      (if (contains? cts/bool-types bool-type)
-        (let [id-ret (atom nil)]
+        (or (not (array? shapes)) (empty? shapes) (not (every? shape/shape-proxy? shapes)))
+        (u/display-not-valid :createBoolean-shapes shapes)
+
+        :else
+        (let [ids (into #{} (map #(obj/get % "$id")) shapes)
+              id-ret (atom nil)]
           (st/emit! (dwb/create-bool bool-type ids {:id-ret id-ret}))
-          (shape/shape-proxy $plugin @id-ret))
-
-        (utils/display-not-valid :bool-shape bool-type)))))
+          (shape/shape-proxy $plugin @id-ret))))))
 
 (defn create-context
   [plugin-id]
diff --git a/frontend/src/app/plugins/file.cljs b/frontend/src/app/plugins/file.cljs
index 1fd74e29e..9f8ca7380 100644
--- a/frontend/src/app/plugins/file.cljs
+++ b/frontend/src/app/plugins/file.cljs
@@ -93,6 +93,9 @@
   {:name js/Symbol.toStringTag
    :get (fn [] (str "FileProxy"))})
 
+(defn file-proxy? [p]
+  (instance? FileProxy p))
+
 (defn file-proxy
   [plugin-id id]
   (crc/add-properties!
diff --git a/frontend/src/app/plugins/flex.cljs b/frontend/src/app/plugins/flex.cljs
index e379fcba4..2f7b50bb7 100644
--- a/frontend/src/app/plugins/flex.cljs
+++ b/frontend/src/app/plugins/flex.cljs
@@ -29,6 +29,9 @@
       (st/emit! (dwt/move-shapes-to-frame #{child-id} $id nil nil)
                 (ptk/data-event :layout/update {:ids [$id]})))))
 
+(defn flex-layout-proxy? [p]
+  (instance? FlexLayout p))
+
 (defn flex-layout-proxy
   [plugin-id file-id page-id id]
   (-> (FlexLayout. plugin-id file-id page-id id)
@@ -151,6 +154,9 @@
 
 (deftype LayoutChildProxy [$plugin $file $page $id])
 
+(defn layout-child-proxy? [p]
+  (instance? LayoutChildProxy p))
+
 (defn layout-child-proxy
   [plugin-id file-id page-id id]
   (-> (LayoutChildProxy. plugin-id file-id page-id id)
diff --git a/frontend/src/app/plugins/fonts.cljs b/frontend/src/app/plugins/fonts.cljs
index 8455ec72b..fec42342d 100644
--- a/frontend/src/app/plugins/fonts.cljs
+++ b/frontend/src/app/plugins/fonts.cljs
@@ -39,6 +39,9 @@
                   :font-weight (d/nilv (obj/get variant "fontWeight") fontWeight)}]
       (st/emit! (dwt/update-text-range id start end values)))))
 
+(defn font-proxy? [p]
+  (instance? PenpotFont p))
+
 (defn font-proxy
   [{:keys [id name variants] :as font}]
   (when (some? font)
diff --git a/frontend/src/app/plugins/grid.cljs b/frontend/src/app/plugins/grid.cljs
index 8b0f49ab9..1d9d4799f 100644
--- a/frontend/src/app/plugins/grid.cljs
+++ b/frontend/src/app/plugins/grid.cljs
@@ -74,6 +74,9 @@
       (st/emit! (dwt/move-shapes-to-frame #{child-id} $id nil [row column])
                 (ptk/data-event :layout/update {:ids [$id]})))))
 
+(defn grid-layout-proxy? [p]
+  (instance? GridLayout p))
+
 (defn grid-layout-proxy
   [plugin-id file-id page-id id]
   (-> (GridLayout. plugin-id file-id page-id id)
@@ -199,6 +202,9 @@
 
 (deftype GridCellProxy [$plugin $file $page $id])
 
+(defn layout-cell-proxy? [p]
+  (instance? GridCellProxy p))
+
 (defn layout-cell-proxy
   [plugin-id file-id page-id id]
   (letfn [(locate-cell [_]
diff --git a/frontend/src/app/plugins/library.cljs b/frontend/src/app/plugins/library.cljs
index 380ff68c3..8107ca375 100644
--- a/frontend/src/app/plugins/library.cljs
+++ b/frontend/src/app/plugins/library.cljs
@@ -137,6 +137,9 @@
       (let [color (u/proxy->library-color self)]
         (apply array (keys (dm/get-in color [:plugin-data (keyword "shared" namespace)])))))))
 
+(defn lib-color-proxy? [p]
+  (instance? LibraryColorProxy p))
+
 (defn lib-color-proxy
   [plugin-id file-id id]
   (assert (uuid? file-id))
@@ -316,6 +319,9 @@
       (let [typography (u/proxy->library-typography self)]
         (apply array (keys (dm/get-in typography [:plugin-data (keyword "shared" namespace)])))))))
 
+(defn lib-typography-proxy? [p]
+  (instance? LibraryTypographyProxy p))
+
 (defn lib-typography-proxy
   [plugin-id file-id id]
   (assert (uuid? file-id))
@@ -522,6 +528,9 @@
       (let [component (u/proxy->library-component self)]
         (apply array (keys (dm/get-in component [:plugin-data (keyword "shared" namespace)])))))))
 
+(defn lib-component-proxy? [p]
+  (instance? LibraryComponentProxy p))
+
 (defn lib-component-proxy
   [plugin-id file-id id]
   (assert (uuid? file-id))
@@ -643,6 +652,9 @@
       (let [file (u/proxy->file self)]
         (apply array (keys (dm/get-in file [:data :plugin-data (keyword "shared" namespace)])))))))
 
+(defn library-proxy? [p]
+  (instance? Library p))
+
 (defn library-proxy
   [plugin-id file-id]
   (assert (uuid? file-id) "File id not valid")
diff --git a/frontend/src/app/plugins/page.cljs b/frontend/src/app/plugins/page.cljs
index 35c1a9dd5..f63cfdd9d 100644
--- a/frontend/src/app/plugins/page.cljs
+++ b/frontend/src/app/plugins/page.cljs
@@ -107,6 +107,9 @@
   {:name js/Symbol.toStringTag
    :get (fn [] (str "PageProxy"))})
 
+(defn page-proxy? [p]
+  (instance? PageProxy p))
+
 (defn page-proxy
   [plugin-id file-id id]
   (crc/add-properties!
diff --git a/frontend/src/app/plugins/shape.cljs b/frontend/src/app/plugins/shape.cljs
index 2048e8afe..5fcf8ce28 100644
--- a/frontend/src/app/plugins/shape.cljs
+++ b/frontend/src/app/plugins/shape.cljs
@@ -380,6 +380,9 @@
   {:name js/Symbol.toStringTag
    :get (fn [] (str "ShapeProxy"))})
 
+(defn shape-proxy? [p]
+  (instance? ShapeProxy p))
+
 (defn shape-proxy
   ([plugin-id id]
    (shape-proxy plugin-id (:current-file-id @st/state) (:current-page-id @st/state) id))
diff --git a/frontend/src/app/plugins/user.cljs b/frontend/src/app/plugins/user.cljs
index eb199f5a6..42cd32f6e 100644
--- a/frontend/src/app/plugins/user.cljs
+++ b/frontend/src/app/plugins/user.cljs
@@ -38,11 +38,17 @@
      {:name "sessionId"
       :get (fn [_] (str session-id))})))
 
+(defn current-user-proxy? [p]
+  (instance? CurrentUserProxy p))
+
 (defn current-user-proxy
   [plugin-id session-id]
   (-> (CurrentUserProxy. plugin-id session-id)
       (add-user-properties)))
 
+(defn active-user-proxy? [p]
+  (instance? ActiveUserProxy p))
+
 (defn active-user-proxy
   [plugin-id session-id]
   (-> (ActiveUserProxy. plugin-id session-id)
diff --git a/frontend/src/app/plugins/viewport.cljs b/frontend/src/app/plugins/viewport.cljs
index 8859f6197..65e4423fb 100644
--- a/frontend/src/app/plugins/viewport.cljs
+++ b/frontend/src/app/plugins/viewport.cljs
@@ -32,7 +32,10 @@
   {:name js/Symbol.toStringTag
    :get (fn [] (str "ViewportProxy"))})
 
-(defn create-proxy
+(defn viewport-proxy? [p]
+  (instance? ViewportProxy p))
+
+(defn viewport-proxy
   [plugin-id]
   (crc/add-properties!
    (ViewportProxy. plugin-id)