diff --git a/src/settings/DeveloperSettingsTab.test.tsx b/src/settings/DeveloperSettingsTab.test.tsx
index c18cf23bb..7bdf7091d 100644
--- a/src/settings/DeveloperSettingsTab.test.tsx
+++ b/src/settings/DeveloperSettingsTab.test.tsx
@@ -79,6 +79,7 @@ describe("DeveloperSettingsTab", () => {
     const { container } = render(
       <DeveloperSettingsTab
         client={client}
+        roomId={"#room:example.org"}
         livekitRooms={livekitRooms}
         env={{ MY_MOCK_ENV: 10, ENV: "test" } as unknown as ImportMetaEnv}
       />,
diff --git a/src/settings/DeveloperSettingsTab.tsx b/src/settings/DeveloperSettingsTab.tsx
index 254aaf0f4..d16e3ef7f 100644
--- a/src/settings/DeveloperSettingsTab.tsx
+++ b/src/settings/DeveloperSettingsTab.tsx
@@ -22,6 +22,7 @@ import {
 import { logger } from "matrix-js-sdk/lib/logger";
 import {
   EditInPlace,
+  ErrorMessage,
   Root as Form,
   Heading,
   HelpMessage,
@@ -45,9 +46,11 @@ import {
 import type { Room as LivekitRoom } from "livekit-client";
 import styles from "./DeveloperSettingsTab.module.css";
 import { useUrlParams } from "../UrlParams";
+import { getSFUConfigWithOpenID } from "../livekit/openIDSFU";
 
 interface Props {
   client: MatrixClient;
+  roomId: string;
   livekitRooms?: { room: LivekitRoom; url: string; isLocal?: boolean }[];
   env: ImportMetaEnv;
 }
@@ -55,6 +58,7 @@ interface Props {
 export const DeveloperSettingsTab: FC<Props> = ({
   client,
   livekitRooms,
+  roomId,
   env,
 }) => {
   const { t } = useTranslation();
@@ -92,6 +96,8 @@ export const DeveloperSettingsTab: FC<Props> = ({
     alwaysShowIphoneEarpieceSetting,
   );
 
+  const [customLivekitUrlUpdateError, setCustomLivekitUrlUpdateError] =
+    useState<string | null>(null);
   const [customLivekitUrl, setCustomLivekitUrl] = useSetting(
     customLivekitUrlSetting,
   );
@@ -229,14 +235,28 @@ export const DeveloperSettingsTab: FC<Props> = ({
         savingLabel={t("developer_mode.custom_livekit_url.saving")}
         cancelButtonLabel={t("developer_mode.custom_livekit_url.reset")}
         onSave={useCallback(
-          (e: React.FormEvent<HTMLFormElement>) => {
-            setCustomLivekitUrl(
-              customLivekitUrlTextBuffer === ""
-                ? null
-                : customLivekitUrlTextBuffer,
-            );
+          async (e: React.FormEvent<HTMLFormElement>): Promise<void> => {
+            if (
+              customLivekitUrlTextBuffer === "" ||
+              customLivekitUrlTextBuffer === null
+            ) {
+              setCustomLivekitUrl(null);
+              return;
+            }
+
+            try {
+              await getSFUConfigWithOpenID(
+                client,
+                customLivekitUrlTextBuffer,
+                roomId,
+              );
+              setCustomLivekitUrlUpdateError(null);
+              setCustomLivekitUrl(customLivekitUrlTextBuffer);
+            } catch {
+              setCustomLivekitUrlUpdateError("invalid URL (did not update)");
+            }
           },
-          [setCustomLivekitUrl, customLivekitUrlTextBuffer],
+          [customLivekitUrlTextBuffer, setCustomLivekitUrl, client, roomId],
         )}
         value={customLivekitUrlTextBuffer ?? ""}
         onChange={useCallback(
@@ -251,7 +271,12 @@ export const DeveloperSettingsTab: FC<Props> = ({
           },
           [setCustomLivekitUrl],
         )}
-      />
+        serverInvalid={customLivekitUrlUpdateError !== null}
+      >
+        {customLivekitUrlUpdateError !== null && (
+          <ErrorMessage>{customLivekitUrlUpdateError}</ErrorMessage>
+        )}
+      </EditInPlace>
       <Heading as="h3" type="body" weight="semibold" size="lg">
         {t("developer_mode.matrixRTCMode.title")}
       </Heading>
diff --git a/src/settings/SettingsModal.tsx b/src/settings/SettingsModal.tsx
index 2b4078aa5..30ac36185 100644
--- a/src/settings/SettingsModal.tsx
+++ b/src/settings/SettingsModal.tsx
@@ -213,6 +213,7 @@ export const SettingsModal: FC<Props> = ({
         env={import.meta.env}
         client={client}
         livekitRooms={livekitRooms}
+        roomId={roomId}
       />
     ),
   };
diff --git a/src/settings/settings.ts b/src/settings/settings.ts
index f85e1414b..03008dca8 100644
--- a/src/settings/settings.ts
+++ b/src/settings/settings.ts
@@ -34,15 +34,20 @@ export class Setting<T> {
 
     this._value$ = new BehaviorSubject(initialValue);
     this.value$ = this._value$;
+    this._lastUpdateReason$ = new BehaviorSubject<string | null>(null);
+    this.lastUpdateReason$ = this._lastUpdateReason$;
   }
 
   private readonly key: string;
 
   private readonly _value$: BehaviorSubject<T>;
+  private readonly _lastUpdateReason$: BehaviorSubject<string | null>;
   public readonly value$: Behavior<T>;
+  public readonly lastUpdateReason$: Behavior<string | null>;
 
-  public readonly setValue = (value: T): void => {
+  public readonly setValue = (value: T, reason?: string): void => {
     this._value$.next(value);
+    this._lastUpdateReason$.next(reason ?? null);
     localStorage.setItem(this.key, JSON.stringify(value));
   };
   public readonly getValue = (): T => {