diff --git a/openflexure_microscope/api/static/src/store.js b/openflexure_microscope/api/static/src/store.js
index 8b92ca38..31f1fd0a 100644
--- a/openflexure_microscope/api/static/src/store.js
+++ b/openflexure_microscope/api/static/src/store.js
@@ -3,9 +3,22 @@ import Vuex from "vuex";
 
 Vue.use(Vuex);
 
+function getOriginFromLocation(){
+  // This will default to the same origin that's serving
+  // the web app - but can be overridden by the URL.
+  // See also devTools.vue which can change the origin.
+  let url = new URL(window.location.href);
+  let origin = url.searchParams.get("overrideOrigin");
+  if(origin){
+    return origin;
+  }else{
+    return url.origin;
+  }
+}
+
 export default new Vuex.Store({
   state: {
-    origin: window.location.origin,
+    origin: getOriginFromLocation(),
     available: false,
     waiting: false,
     error: "",