diff --git a/src/App.jsx b/src/App.jsx
index bb3fc6f..4b3d261 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -36,6 +36,12 @@ import {
   migrateLegacySearxUrl,
   resolveBackendApiUrl,
 } from './appConfig'
+import {
+  expectBackendJson,
+  getErrorText,
+  isAbortError,
+  readBackendErrorText,
+} from './backendApi'
 import { sanitizeChatTitle, splitThinkBlocks } from './chatText'
 import { buildModelPickerOptions } from './modelPicker'
 import {
@@ -217,45 +223,10 @@ export default function App() {
     )
   }
 
-  function isAbortError(error) {
-    return error?.name === 'AbortError'
-  }
-
   function messageHasImageAttachments(message) {
     return Array.isArray(message?.attachments) && message.attachments.some(attachmentIsImage)
   }
 
-  function getErrorText(error) {
-    if (error instanceof Error && error.message) return error.message
-    return String(error)
-  }
-
-  async function readBackendErrorText(response) {
-    const bodyText = await response.text().catch(() => '')
-    if (bodyText) {
-      try {
-        const data = JSON.parse(bodyText)
-        if (typeof data?.detail === 'string' && data.detail.trim()) {
-          return data.detail.trim()
-        }
-        if (typeof data?.message === 'string' && data.message.trim()) {
-          return data.message.trim()
-        }
-      } catch {}
-      return bodyText.trim()
-    }
-    return `HTTP ${response.status}`
-  }
-
-  async function expectBackendJson(response) {
-    const data = await response.json().catch(() => null)
-    if (response.ok) return data
-    const detail = typeof data?.detail === 'string'
-      ? data.detail
-      : (typeof data?.message === 'string' ? data.message : '')
-    throw new Error(detail || `HTTP ${response.status}`)
-  }
-
   async function fetchModelCapabilities(modelName, signal) {
     const response = await fetch(
       `${backendApiUrl}/models/capabilities?name=${encodeURIComponent(modelName)}`,
diff --git a/src/backendApi.js b/src/backendApi.js
new file mode 100644
index 0000000..6cb2555
--- /dev/null
+++ b/src/backendApi.js
@@ -0,0 +1,34 @@
+export function isAbortError(error) {
+  return error?.name === 'AbortError'
+}
+
+export function getErrorText(error) {
+  if (error instanceof Error && error.message) return error.message
+  return String(error)
+}
+
+export async function readBackendErrorText(response) {
+  const bodyText = await response.text().catch(() => '')
+  if (bodyText) {
+    try {
+      const data = JSON.parse(bodyText)
+      if (typeof data?.detail === 'string' && data.detail.trim()) {
+        return data.detail.trim()
+      }
+      if (typeof data?.message === 'string' && data.message.trim()) {
+        return data.message.trim()
+      }
+    } catch {}
+    return bodyText.trim()
+  }
+  return `HTTP ${response.status}`
+}
+
+export async function expectBackendJson(response) {
+  const data = await response.json().catch(() => null)
+  if (response.ok) return data
+  const detail = typeof data?.detail === 'string'
+    ? data.detail
+    : (typeof data?.message === 'string' ? data.message : '')
+  throw new Error(detail || `HTTP ${response.status}`)
+}