diff --git a/packages/web/src/stores/spaceStore.joinByCode.test.ts b/packages/web/src/stores/spaceStore.joinByCode.test.ts
new file mode 100644
index 00000000..4ac00a43
--- /dev/null
+++ b/packages/web/src/stores/spaceStore.joinByCode.test.ts
@@ -0,0 +1,92 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// Stub AudioManager to avoid AudioWorkletNode reference error in jsdom
+vi.mock('../audio/AudioManager', () => ({
+  AudioManager: {
+    getInstance: vi.fn().mockReturnValue({
+      setOutputDevice: vi.fn(),
+      setVolume: vi.fn(),
+    }),
+  },
+}));
+
+// Stub instanceStore to avoid initialization ordering issues
+vi.mock('./instanceStore', () => ({
+  useInstanceStore: Object.assign(
+    (selector: (s: unknown) => unknown) => selector({ instances: [], _autoConnectDone: true }),
+    {
+      getState: () => ({ instances: [], _autoConnectDone: true }),
+      setState: vi.fn(),
+      subscribe: vi.fn(),
+    }
+  ),
+}));
+
+// Stub authStore to avoid localStorage access during module init
+vi.mock('./authStore', () => ({
+  useAuthStore: Object.assign(
+    (selector: (s: unknown) => unknown) => selector({ user: null, token: null }),
+    {
+      getState: () => ({ user: null, token: null }),
+      setState: vi.fn(),
+      subscribe: vi.fn(),
+    }
+  ),
+}));
+
+// Stub the api client — use vi.fn() inline (hoisting constraint)
+vi.mock('../api/client', () => ({
+  api: {
+    spaces: { joinByCode: vi.fn() },
+  },
+  BackspaceApiClient: vi.fn(),
+}));
+
+// Stub crossStoreResolvers — use vi.fn() inline
+vi.mock('../utils/crossStoreResolvers', () => ({
+  getApiForOrigin: vi.fn(),
+  resolveOriginFromHostname: vi.fn(),
+  resolveUserIdFromInstances: vi.fn(),
+  getCachedUserIdForOrigin: vi.fn(),
+  clearMyUserIdCache: vi.fn(),
+}));
+
+// Import after mocks so we get the mocked versions
+import { useSpaceStore } from './spaceStore';
+import { api } from '../api/client';
+import { getApiForOrigin } from '../utils/crossStoreResolvers';
+
+const FAKE_SPACE = {
+  id: 'S1',
+  name: 'Aether',
+  icon: null,
+  banner: null,
+  _instanceOrigin: '',
+  description: null,
+  isPublic: false,
+  isDiscoverable: false,
+  ownerId: 'U1',
+  createdAt: 1000,
+  memberCount: 1,
+};
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  useSpaceStore.getState().reset();
+  (api.spaces.joinByCode as ReturnType<typeof vi.fn>).mockResolvedValue(FAKE_SPACE);
+});
+
+describe('spaceStore.joinByCode — origin normalization', () => {
+  it('treats explicit home origin as local (does NOT call getApiForOrigin)', async () => {
+    const homeOrigin = window.location.origin;
+    await useSpaceStore.getState().joinByCode('abc', homeOrigin);
+    expect(api.spaces.joinByCode).toHaveBeenCalledTimes(1);
+    expect(getApiForOrigin).not.toHaveBeenCalled();
+  });
+
+  it('treats undefined origin as local (existing behavior preserved)', async () => {
+    await useSpaceStore.getState().joinByCode('abc');
+    expect(api.spaces.joinByCode).toHaveBeenCalledTimes(1);
+    expect(getApiForOrigin).not.toHaveBeenCalled();
+  });
+});
diff --git a/packages/web/src/stores/spaceStore.ts b/packages/web/src/stores/spaceStore.ts
index df4f424b..6d953950 100644
--- a/packages/web/src/stores/spaceStore.ts
+++ b/packages/web/src/stores/spaceStore.ts
@@ -347,6 +347,11 @@ export const useSpaceStore = create<SpaceState>((set, get) => ({
   },
 
   joinByCode: async (inviteCode: string, origin?: string) => {
+    // Normalize: an explicit home origin is equivalent to undefined (local).
+    // Mirrors inviteParser's same normalization at the URL boundary.
+    if (origin && typeof window !== 'undefined' && origin === window.location.origin) {
+      origin = undefined;
+    }
     if (origin) {
       // Remote instance — verify connectivity via dynamic import (avoids circular dep)
       const { useInstanceStore } = await import('./instanceStore');