diff --git a/backend/src/app/rpc/mutations/fonts.clj b/backend/src/app/rpc/mutations/fonts.clj
index fd3291e6d..85c604b15 100644
--- a/backend/src/app/rpc/mutations/fonts.clj
+++ b/backend/src/app/rpc/mutations/fonts.clj
@@ -6,6 +6,7 @@
 
 (ns app.rpc.mutations.fonts
   (:require
+   [app.common.exceptions :as ex]
    [app.common.spec :as us]
    [app.common.uuid :as uuid]
    [app.config :as cf]
@@ -49,6 +50,7 @@
   (let [data    (media/run cfg {:cmd :generate-fonts :input data :rlimit :font})
         storage (media/configure-assets-storage storage conn)
 
+
         otf     (when-let [fdata (get data "font/otf")]
                   (sto/put-object storage {:content (sto/content fdata)
                                            :content-type "font/otf"}))
@@ -65,6 +67,13 @@
                   (sto/put-object storage {:content (sto/content fdata)
                                            :content-type "font/woff2"}))]
 
+    (when (and (nil? otf)
+               (nil? ttf)
+               (nil? woff1)
+               (nil? woff2))
+      (ex/raise :type :validation
+                :code :invalid-font-upload))
+
     (db/insert! conn :team-font-variant
                 {:id (uuid/next)
                  :team-id (:team-id params)
diff --git a/frontend/src/app/main/data/fonts.cljs b/frontend/src/app/main/data/fonts.cljs
index 74872995b..a8ecf7127 100644
--- a/frontend/src/app/main/data/fonts.cljs
+++ b/frontend/src/app/main/data/fonts.cljs
@@ -111,10 +111,13 @@
                                            (:data content)})
                              (dissoc :content)))))))
 
-          (parse-mtype [mtype]
-            (case mtype
-              "application/vnd.oasis.opendocument.formula-template" "font/otf"
-              mtype))
+          (parse-mtype [ba]
+            (let [u8 (js/Uint8Array. ba 0 4)
+                  sg (areduce u8 i ret "" (str ret (if (zero? i) "" " ") (.toString (aget u8 i) 8)))]
+              (case sg
+                "117 124 124 117" "font/otf"
+                "0 1 0 0"         "font/ttf"
+                "167 117 106 106" "font/woff")))
 
           (parse-font [{:keys [data] :as params}]
             (try
@@ -128,7 +131,11 @@
                  (rx/map (fn [data]
                            {:data data
                             :name (.-name blob)
-                            :type (parse-mtype (.-type blob))}))))]
+                            :type (parse-mtype data)}))
+                 (rx/mapcat (fn [{:keys [type] :as font}]
+                              (if type
+                                (rx/of font)
+                                (rx/empty))))))]
 
     (->> (rx/from blobs)
          (rx/mapcat read-blob)