diff --git a/apps/ai-game-creator-shell/src-tauri/src/ui_editor/component/text.rs b/apps/ai-game-creator-shell/src-tauri/src/ui_editor/component/text.rs
index 092e8fc0c..46291e831 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/ui_editor/component/text.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/ui_editor/component/text.rs
@@ -2,7 +2,7 @@ use crate::ui_editor::component::common::error::ComponentValueError;
 use crate::ui_editor::resource::sprite::{Color, WHITE};
 use crate::ui_editor::utils::FontAssetId;
 use schemars::JsonSchema;
-use serde::{Deserialize, Serialize};
+use serde::{de::Deserializer, Deserialize, Serialize};
 use std::num::NonZeroU32;
 use ts_rs::TS;
 use typed_floats::tf32::StrictlyPositiveFinite;
@@ -44,13 +44,29 @@ pub enum VerticalTextOverflow {
     Overflow,
 }
 
-#[derive(Clone, Copy, Debug, Deserialize, JsonSchema, PartialEq, Serialize, TS)]
+#[derive(Clone, Copy, Debug, JsonSchema, PartialEq, Serialize, TS)]
 #[ts(export, export_to = concat!(env!("CARGO_MANIFEST_DIR"), "/../src/features/ui-editor/types/"))]
 pub struct BestFitFontSize {
     min: NonZeroU32,
     max: NonZeroU32,
 }
 
+impl<'de> Deserialize<'de> for BestFitFontSize {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        #[derive(Deserialize)]
+        struct RawBestFitFontSize {
+            min: NonZeroU32,
+            max: NonZeroU32,
+        }
+
+        let raw = RawBestFitFontSize::deserialize(deserializer)?;
+        Self::new(raw.min, raw.max).map_err(serde::de::Error::custom)
+    }
+}
+
 impl BestFitFontSize {
     pub fn new(min: NonZeroU32, max: NonZeroU32) -> Result<Self, ComponentValueError> {
         if min > max {
@@ -129,6 +145,29 @@ impl Default for TextComponent {
     }
 }
 
+#[cfg(test)]
+mod best_fit_tests {
+    use super::{BestFitFontSize, FontSizing};
+
+    #[test]
+    fn best_fit_font_size_is_validated_when_deserialized() {
+        let valid: BestFitFontSize =
+            serde_json::from_value(serde_json::json!({ "min": 12, "max": 24 }))
+                .expect("valid font-size range");
+        assert_eq!(valid.min().get(), 12);
+        assert_eq!(valid.max().get(), 24);
+
+        assert!(serde_json::from_value::<BestFitFontSize>(
+            serde_json::json!({ "min": 24, "max": 12 }),
+        )
+        .is_err());
+        assert!(serde_json::from_value::<FontSizing>(
+            serde_json::json!({ "BestFit": { "min": 24, "max": 12 } }),
+        )
+        .is_err());
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;