diff --git a/packages/code-gen/src/api-client/js-axios.js b/packages/code-gen/src/api-client/js-axios.js
index f1755d9273..0deec8861c 100644
--- a/packages/code-gen/src/api-client/js-axios.js
+++ b/packages/code-gen/src/api-client/js-axios.js
@@ -245,6 +245,11 @@ export function jsAxiosGenerateFunction(
           file,
           `data.append("${key}", ${parameter}["${key}"].data, ${parameter}["${key}"].name);`,
         );
+      } else if (fieldType.type === "number") {
+        fileWrite(
+          file,
+          `data.append("${key}", ${parameter}["${key}"].toString());`,
+        );
       } else {
         fileWrite(file, `data.append("${key}", ${parameter}["${key}"]);`);
       }
diff --git a/packages/code-gen/src/api-client/react-query.js b/packages/code-gen/src/api-client/react-query.js
index 406f8e75f9..3db65fda6a 100644
--- a/packages/code-gen/src/api-client/react-query.js
+++ b/packages/code-gen/src/api-client/react-query.js
@@ -608,7 +608,7 @@ ${hookName}.setQueryData = (
         })},`
       : ""
   }
-  data: Updater<${contextNames.responseTypeName ?? "unknown"}, ${
+  data: Updater<${contextNames.responseTypeName ?? "unknown"} | undefined, ${
     contextNames.responseTypeName ?? "unknown"
   }>,
 ) => {
diff --git a/packages/code-gen/src/api-client/ts-axios.js b/packages/code-gen/src/api-client/ts-axios.js
index 45f5af6246..38edba7ae7 100644
--- a/packages/code-gen/src/api-client/ts-axios.js
+++ b/packages/code-gen/src/api-client/ts-axios.js
@@ -209,6 +209,11 @@ export function tsAxiosGenerateFunction(
             `data.append("${key}", ${parameter}["${key}"].data, ${parameter}["${key}"].name);`,
           );
         }
+      } else if (fieldType.type === "number") {
+        fileWrite(
+          file,
+          `data.append("${key}", ${parameter}["${key}"].toString());`,
+        );
       } else {
         fileWrite(file, `data.append("${key}", ${parameter}["${key}"]);`);
       }
diff --git a/packages/code-gen/src/api-client/ts-fetch.js b/packages/code-gen/src/api-client/ts-fetch.js
index 8819a6874a..34d57385bc 100644
--- a/packages/code-gen/src/api-client/ts-fetch.js
+++ b/packages/code-gen/src/api-client/ts-fetch.js
@@ -269,6 +269,11 @@ export function tsFetchGenerateFunction(
             `data.append("${key}", ${parameter}["${key}"].data, ${parameter}["${key}"].name);`,
           );
         }
+      } else if (fieldType.type === "number") {
+        fileWrite(
+          file,
+          `data.append("${key}", ${parameter}["${key}"].toString());`,
+        );
       } else {
         fileWrite(file, `data.append("${key}", ${parameter}["${key}"]);`);
       }