diff --git a/src/public/app/widgets/type_widgets/options/appearance/fonts.ts b/src/public/app/widgets/type_widgets/options/appearance/fonts.ts
index a5658c4b1..a83980fcf 100644
--- a/src/public/app/widgets/type_widgets/options/appearance/fonts.ts
+++ b/src/public/app/widgets/type_widgets/options/appearance/fonts.ts
@@ -1,9 +1,19 @@
 import OptionsWidget from "../options_widget.js";
 import utils from "../../../../services/utils.js";
 import { t } from "../../../../services/i18n.js";
-import { OptionMap, OptionNames } from "../../../../../../services/options_interface.js";
+import { FontFamily, OptionMap, OptionNames } from "../../../../../../services/options_interface.js";
 
-const FONT_FAMILIES = [
+interface FontFamilyEntry {
+    value: FontFamily;
+    label: string;
+}
+
+interface FontGroup {
+    title: string;
+    items: FontFamilyEntry[];
+}
+
+const FONT_FAMILIES: FontGroup[] = [
     {
         title: t("fonts.generic-fonts"),
         items: [
diff --git a/src/services/options_interface.ts b/src/services/options_interface.ts
index 6ea40dd8c..3cbdfa6ef 100644
--- a/src/services/options_interface.ts
+++ b/src/services/options_interface.ts
@@ -12,6 +12,8 @@ type KeyboardShortcutsOptions<T extends KeyboardActionNames> = {
     [key in T as `keyboardShortcuts${Capitalize<key>}`]: string
 };
 
+export type FontFamily = "theme" | "serif" | "sans-serif" | "monospace" | string;
+
 export interface OptionDefinitions extends KeyboardShortcutsOptions<KeyboardActionNames> {
     "openNoteContexts": string;
     "lastDailyBackupDate": string;
@@ -22,10 +24,10 @@ export interface OptionDefinitions extends KeyboardShortcutsOptions<KeyboardActi
     "syncServerHost": string;
     "syncServerTimeout": string;
     "syncProxy": string;
-    "mainFontFamily": string;
-    "treeFontFamily": string;
-    "detailFontFamily": string;
-    "monospaceFontFamily": string;
+    "mainFontFamily": FontFamily;
+    "treeFontFamily": FontFamily;
+    "detailFontFamily": FontFamily;
+    "monospaceFontFamily": FontFamily;
     "spellCheckLanguageCode": string;
     "codeNotesMimeTypes": string;
     "headingStyle": string;