diff --git a/spiffworkflow-frontend/src/routes/Extension.tsx b/spiffworkflow-frontend/src/routes/Extension.tsx
index 75e8fe3af..1319eb7bb 100644
--- a/spiffworkflow-frontend/src/routes/Extension.tsx
+++ b/spiffworkflow-frontend/src/routes/Extension.tsx
@@ -286,7 +286,7 @@ export default function Extension({
       if (pageComponent && pageComponent.on_form_submit) {
         apiPathRaw = pageComponent.on_form_submit.api_path.replace(/^\/?/, '/');
         if (!pageComponent.on_form_submit.is_full_api_path) {
-          apiPathRaw = `${targetUris.extensionListPath}/${apiPathRaw}`;
+          apiPathRaw = `${targetUris.extensionListPath}${apiPathRaw}`;
         } else {
           postBody = dataToSubmit;
         }