diff --git a/src/config/comfyApi.test.ts b/src/config/comfyApi.test.ts
new file mode 100644
index 00000000000..681428ca561
--- /dev/null
+++ b/src/config/comfyApi.test.ts
@@ -0,0 +1,101 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { refreshRemoteConfig } from '@/platform/remoteConfig/refreshRemoteConfig'
+import { remoteConfig } from '@/platform/remoteConfig/remoteConfig'
+
+import { getComfyApiBaseUrl, getComfyPlatformBaseUrl } from './comfyApi'
+
+vi.mock('@/scripts/api', () => ({
+  api: {
+    apiURL: (route: string) => `/api${route}`,
+    fetchApi: vi.fn()
+  }
+}))
+
+vi.stubGlobal('fetch', vi.fn())
+
+describe('getComfyApiBaseUrl', () => {
+  const originalConfig = remoteConfig.value
+
+  beforeEach(() => {
+    remoteConfig.value = {}
+  })
+
+  afterEach(() => {
+    remoteConfig.value = originalConfig
+  })
+
+  it('honors the server-provided override', () => {
+    remoteConfig.value = { comfy_api_base_url: 'https://my-ephem.example.com' }
+    expect(getComfyApiBaseUrl()).toBe('https://my-ephem.example.com')
+  })
+
+  it('falls back to the build-time default when the key is absent', () => {
+    expect(getComfyApiBaseUrl()).toBe('https://stagingapi.comfy.org')
+  })
+
+  it('falls back to the build-time default when the value is empty', () => {
+    remoteConfig.value = { comfy_api_base_url: '' }
+    expect(getComfyApiBaseUrl()).toBe('https://stagingapi.comfy.org')
+  })
+})
+
+describe('getComfyPlatformBaseUrl', () => {
+  const originalConfig = remoteConfig.value
+
+  beforeEach(() => {
+    remoteConfig.value = {}
+  })
+
+  afterEach(() => {
+    remoteConfig.value = originalConfig
+  })
+
+  it('honors the server-provided override', () => {
+    remoteConfig.value = {
+      comfy_platform_base_url: 'https://my-ephem-platform.example.com'
+    }
+    expect(getComfyPlatformBaseUrl()).toBe(
+      'https://my-ephem-platform.example.com'
+    )
+  })
+
+  it('falls back to the build-time default when the key is absent', () => {
+    expect(getComfyPlatformBaseUrl()).toBe('https://stagingplatform.comfy.org')
+  })
+
+  it('falls back to the build-time default when the value is empty', () => {
+    remoteConfig.value = { comfy_platform_base_url: '' }
+    expect(getComfyPlatformBaseUrl()).toBe('https://stagingplatform.comfy.org')
+  })
+})
+
+describe('compatibility with comfyui servers that predate the override keys', () => {
+  const originalConfig = remoteConfig.value
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    remoteConfig.value = {}
+  })
+
+  afterEach(() => {
+    remoteConfig.value = originalConfig
+  })
+
+  it('falls back to build-time defaults when /features omits the URL keys', async () => {
+    // An older comfyui server has /features but doesn't know about
+    // comfy_api_base_url / comfy_platform_base_url yet.
+    vi.mocked(global.fetch).mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        supports_preview_metadata: true,
+        max_upload_size: 104857600
+      })
+    } as Response)
+
+    await refreshRemoteConfig({ useAuth: false })
+
+    expect(getComfyApiBaseUrl()).toBe('https://stagingapi.comfy.org')
+    expect(getComfyPlatformBaseUrl()).toBe('https://stagingplatform.comfy.org')
+  })
+})
diff --git a/src/config/comfyApi.ts b/src/config/comfyApi.ts
index b6a8e375af4..86e3c5ce8c7 100644
--- a/src/config/comfyApi.ts
+++ b/src/config/comfyApi.ts
@@ -1,4 +1,3 @@
-import { isCloud } from '@/platform/distribution/types'
 import {
   configValueOrDefault,
   remoteConfig
@@ -20,10 +19,6 @@ const BUILD_TIME_PLATFORM_BASE_URL = __USE_PROD_CONFIG__
     STAGING_PLATFORM_BASE_URL)
 
 export function getComfyApiBaseUrl(): string {
-  if (!isCloud) {
-    return BUILD_TIME_API_BASE_URL
-  }
-
   return configValueOrDefault(
     remoteConfig.value,
     'comfy_api_base_url',
@@ -32,10 +27,6 @@ export function getComfyApiBaseUrl(): string {
 }
 
 export function getComfyPlatformBaseUrl(): string {
-  if (!isCloud) {
-    return BUILD_TIME_PLATFORM_BASE_URL
-  }
-
   return configValueOrDefault(
     remoteConfig.value,
     'comfy_platform_base_url',
diff --git a/src/config/firebase.test.ts b/src/config/firebase.test.ts
new file mode 100644
index 00000000000..b96de30b9b6
--- /dev/null
+++ b/src/config/firebase.test.ts
@@ -0,0 +1,45 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+async function loadFirebase(useProdConfig: boolean) {
+  vi.resetModules()
+  vi.stubGlobal('__USE_PROD_CONFIG__', useProdConfig)
+  const { remoteConfig } = await import('@/platform/remoteConfig/remoteConfig')
+  const { getFirebaseConfig } = await import('./firebase')
+  return { getFirebaseConfig, remoteConfig }
+}
+
+describe('getFirebaseConfig', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('honors a full server-provided firebase_config (cloud builds)', async () => {
+    const cloud = {
+      apiKey: 'cloud-key',
+      authDomain: 'cloud.example.com',
+      projectId: 'some-cloud-project',
+      storageBucket: 'cloud.appspot.com',
+      messagingSenderId: '1',
+      appId: '1:1:web:abc'
+    }
+    const { getFirebaseConfig, remoteConfig } = await loadFirebase(true)
+    remoteConfig.value = { firebase_config: cloud }
+    expect(getFirebaseConfig()).toEqual(cloud)
+  })
+
+  it('uses the dev project when the server reports firebase_env "dev", even if the build-time fallback is prod', async () => {
+    const { getFirebaseConfig, remoteConfig } = await loadFirebase(true)
+    remoteConfig.value = { firebase_env: 'dev' }
+    expect(getFirebaseConfig().projectId).toBe('dreamboothy-dev')
+  })
+
+  it('falls back to the build-time config when the server reports no firebase_env', async () => {
+    const prod = await loadFirebase(true)
+    prod.remoteConfig.value = {}
+    expect(prod.getFirebaseConfig().projectId).toBe('dreamboothy')
+
+    const dev = await loadFirebase(false)
+    dev.remoteConfig.value = {}
+    expect(dev.getFirebaseConfig().projectId).toBe('dreamboothy-dev')
+  })
+})
diff --git a/src/config/firebase.ts b/src/config/firebase.ts
index e976a2ef605..90ad7e92e2b 100644
--- a/src/config/firebase.ts
+++ b/src/config/firebase.ts
@@ -1,6 +1,5 @@
 import type { FirebaseOptions } from 'firebase/app'
 
-import { isCloud } from '@/platform/distribution/types'
 import { remoteConfig } from '@/platform/remoteConfig/remoteConfig'
 
 const DEV_CONFIG: FirebaseOptions = {
@@ -28,15 +27,12 @@ const PROD_CONFIG: FirebaseOptions = {
 const BUILD_TIME_CONFIG = __USE_PROD_CONFIG__ ? PROD_CONFIG : DEV_CONFIG
 
 /**
- * Returns the Firebase configuration for the current environment.
- * - Cloud builds use runtime configuration delivered via feature flags
- * - OSS / localhost builds fall back to the build-time config determined by __USE_PROD_CONFIG__
+ * Firebase config for the current backend: the server's firebase_config (cloud builds),
+ * else the bundled DEV_CONFIG when the server reports a dev-tier backend, else the build-time default.
  */
 export function getFirebaseConfig(): FirebaseOptions {
-  if (!isCloud) {
-    return BUILD_TIME_CONFIG
-  }
-
   const runtimeConfig = remoteConfig.value.firebase_config
-  return runtimeConfig ?? BUILD_TIME_CONFIG
+  if (runtimeConfig) return runtimeConfig
+  if (remoteConfig.value.firebase_env === 'dev') return DEV_CONFIG
+  return BUILD_TIME_CONFIG
 }
diff --git a/src/main.ts b/src/main.ts
index e120d704309..9e05dfaf57c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -32,13 +32,12 @@ import { i18n } from './i18n'
 
 const isCloud = __DISTRIBUTION__ === 'cloud'
 const hasHostTelemetryBridge = Boolean(window.__comfyDesktop2?.Telemetry)
-const requiresRemoteConfigBootstrap = isCloud || hasHostTelemetryBridge
 
-if (requiresRemoteConfigBootstrap) {
-  const { refreshRemoteConfig } =
-    await import('@/platform/remoteConfig/refreshRemoteConfig')
-  await refreshRemoteConfig({ useAuth: false })
-}
+// Load remote config before initializeApp() below, so getFirebaseConfig() resolves
+// against the server's runtime values instead of the build-time defaults.
+const { refreshRemoteConfig } =
+  await import('@/platform/remoteConfig/refreshRemoteConfig')
+await refreshRemoteConfig({ useAuth: false })
 
 if (isCloud) {
   const { initTelemetry } = await import('@/platform/telemetry/initTelemetry')
diff --git a/src/platform/remoteConfig/refreshRemoteConfig.test.ts b/src/platform/remoteConfig/refreshRemoteConfig.test.ts
index f947b822cb2..53a5fde8b8f 100644
--- a/src/platform/remoteConfig/refreshRemoteConfig.test.ts
+++ b/src/platform/remoteConfig/refreshRemoteConfig.test.ts
@@ -7,7 +7,8 @@ import { remoteConfig } from './remoteConfig'
 
 vi.mock('@/scripts/api', () => ({
   api: {
-    fetchApi: vi.fn()
+    fetchApi: vi.fn(),
+    apiURL: vi.fn((route: string) => `/ComfyUI/api${route}`)
   }
 }))
 
@@ -43,9 +44,10 @@ describe('refreshRemoteConfig', () => {
 
       await refreshRemoteConfig({ useAuth: true })
 
-      expect(api.fetchApi).toHaveBeenCalledWith('/features', {
-        cache: 'no-store'
-      })
+      expect(api.fetchApi).toHaveBeenCalledWith(
+        '/features',
+        expect.objectContaining({ cache: 'no-store' })
+      )
       expect(global.fetch).not.toHaveBeenCalled()
       expect(remoteConfig.value).toEqual(mockConfig)
       expect(window.__CONFIG__).toEqual(mockConfig)
@@ -59,23 +61,56 @@ describe('refreshRemoteConfig', () => {
       expect(api.fetchApi).toHaveBeenCalled()
       expect(global.fetch).not.toHaveBeenCalled()
     })
+
+    it('does not pass an abort signal on the authed branch (so it is never aborted)', async () => {
+      vi.mocked(api.fetchApi).mockResolvedValue(mockSuccessResponse())
+
+      await refreshRemoteConfig({ useAuth: true })
+
+      const init = vi.mocked(api.fetchApi).mock.calls[0][1]
+      expect(init?.signal).toBeUndefined()
+    })
   })
 
   describe('without auth', () => {
-    it('uses raw fetch when useAuth is false', async () => {
+    it('builds the no-auth url via api.apiURL so a path prefix is respected', async () => {
       vi.mocked(global.fetch).mockResolvedValue(mockSuccessResponse())
 
       await refreshRemoteConfig({ useAuth: false })
 
-      expect(global.fetch).toHaveBeenCalledWith('/api/features', {
-        cache: 'no-store'
-      })
+      expect(api.apiURL).toHaveBeenCalledWith('/features')
+      expect(global.fetch).toHaveBeenCalledWith(
+        '/ComfyUI/api/features',
+        expect.objectContaining({ cache: 'no-store' })
+      )
       expect(api.fetchApi).not.toHaveBeenCalled()
       expect(remoteConfig.value).toEqual(mockConfig)
       expect(window.__CONFIG__).toEqual(mockConfig)
     })
   })
 
+  describe('timeout', () => {
+    it('passes an AbortSignal so a wedged /features cannot hang startup', async () => {
+      vi.mocked(global.fetch).mockResolvedValue(mockSuccessResponse())
+
+      await refreshRemoteConfig({ useAuth: false })
+
+      const init = vi.mocked(global.fetch).mock.calls[0][1]
+      expect(init?.signal).toBeInstanceOf(AbortSignal)
+    })
+
+    it('falls back to empty config when the request aborts', async () => {
+      vi.mocked(global.fetch).mockRejectedValue(
+        new DOMException('Aborted', 'AbortError')
+      )
+
+      await refreshRemoteConfig({ useAuth: false })
+
+      expect(remoteConfig.value).toEqual({})
+      expect(window.__CONFIG__).toEqual({})
+    })
+  })
+
   describe('error handling', () => {
     it('clears config on 401 response', async () => {
       vi.mocked(api.fetchApi).mockResolvedValue(
diff --git a/src/platform/remoteConfig/refreshRemoteConfig.ts b/src/platform/remoteConfig/refreshRemoteConfig.ts
index 449be328fd3..effaf4e60d0 100644
--- a/src/platform/remoteConfig/refreshRemoteConfig.ts
+++ b/src/platform/remoteConfig/refreshRemoteConfig.ts
@@ -4,6 +4,11 @@ import {
   remoteConfigState
 } from './remoteConfig'
 
+// Cap the bootstrap fetch so a wedged /features endpoint can never block app.mount indefinitely.
+// A same-origin GET against the local comfyui server should resolve in well under a second;
+// on timeout the catch below clears remoteConfig and consumers fall back to build-time defaults.
+const FEATURES_FETCH_TIMEOUT_MS = 5_000
+
 interface RefreshRemoteConfigOptions {
   /**
    * Whether to use authenticated API (default: true).
@@ -12,10 +17,14 @@ interface RefreshRemoteConfigOptions {
   useAuth?: boolean
 }
 
-async function fetchRemoteConfig(useAuth: boolean): Promise<Response> {
-  if (!useAuth) return fetch('/api/features', { cache: 'no-store' })
-
+async function fetchRemoteConfig(
+  useAuth: boolean,
+  signal?: AbortSignal
+): Promise<Response> {
   const { api } = await import('@/scripts/api')
+  if (!useAuth) {
+    return fetch(api.apiURL('/features'), { cache: 'no-store', signal })
+  }
   return api.fetchApi('/features', { cache: 'no-store' })
 }
 
@@ -33,8 +42,13 @@ export async function refreshRemoteConfig(
 ): Promise<void> {
   const { useAuth = true } = options
 
+  const controller = useAuth ? null : new AbortController()
+  const timeoutId = controller
+    ? setTimeout(() => controller.abort(), FEATURES_FETCH_TIMEOUT_MS)
+    : null
+
   try {
-    const response = await fetchRemoteConfig(useAuth)
+    const response = await fetchRemoteConfig(useAuth, controller?.signal)
 
     if (response.ok) {
       const config = await response.json()
@@ -59,5 +73,7 @@ export async function refreshRemoteConfig(
     window.__CONFIG__ = {}
     remoteConfig.value = {}
     remoteConfigState.value = 'error'
+  } finally {
+    if (timeoutId !== null) clearTimeout(timeoutId)
   }
 }
diff --git a/src/platform/remoteConfig/types.ts b/src/platform/remoteConfig/types.ts
index a2c65fc0511..c967406d205 100644
--- a/src/platform/remoteConfig/types.ts
+++ b/src/platform/remoteConfig/types.ts
@@ -93,6 +93,7 @@ export type RemoteConfig = {
   comfy_api_base_url?: string
   comfy_platform_base_url?: string
   firebase_config?: FirebaseRuntimeConfig
+  firebase_env?: 'dev'
   telemetry_disabled_events?: TelemetryEventName[]
   enable_telemetry?: boolean
   model_upload_button_enabled?: boolean