diff --git a/api/be1.js b/api/be1.js
deleted file mode 100644
index 13e0ea6..0000000
--- a/api/be1.js
+++ /dev/null
@@ -1,8 +0,0 @@
-const { proxyRequest } = require('./_proxy');
-
-module.exports = function handler(request, response) {
-  return proxyRequest(request, response, {
-    envName: 'BE1_PROXY_TARGET_URL',
-    pathQueryParam: 'path',
-  });
-};
diff --git a/api/be3.js b/api/be3.js
deleted file mode 100644
index b014c05..0000000
--- a/api/be3.js
+++ /dev/null
@@ -1,8 +0,0 @@
-const { proxyRequest } = require('./_proxy');
-
-module.exports = function handler(request, response) {
-  return proxyRequest(request, response, {
-    envName: 'BE3_PROXY_TARGET_URL',
-    pathQueryParam: 'path',
-  });
-};
diff --git a/package.json b/package.json
index 871edaf..239e4ce 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
       "lodash": "^4.18.1",
       "picomatch@^2.3.1": "^2.3.2",
       "picomatch@^4.0.3": "^4.0.4",
+      "postcss": "^8.5.10",
       "yaml": "^2.8.3"
     }
   },
@@ -64,7 +65,7 @@
     "@tanstack/react-router": "^1.166.3",
     "@vanilla-extract/css": "^1.18.0",
     "antd": "^6.3.2",
-    "axios": "1.15.1",
+    "axios": "1.15.2",
     "react": "^19.1.1",
     "react-dom": "^19.1.1",
     "zustand": "5.0.12"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bf6b0a7..ddbf624 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -11,6 +11,7 @@ overrides:
   lodash: ^4.18.1
   picomatch@^2.3.1: ^2.3.2
   picomatch@^4.0.3: ^4.0.4
+  postcss: ^8.5.10
   yaml: ^2.8.3
 
 importers:
@@ -26,8 +27,8 @@ importers:
         specifier: ^6.3.2
         version: 6.3.2(react-dom@19.2.4(react@19.2.4))(react@19.2.4)
       axios:
-        specifier: 1.15.1
-        version: 1.15.1
+        specifier: 1.15.2
+        version: 1.15.2
       react:
         specifier: ^19.1.1
         version: 19.2.4
@@ -1875,10 +1876,10 @@ packages:
       }
     engines: { node: '>= 0.4' }
 
-  axios@1.15.1:
+  axios@1.15.2:
     resolution:
       {
-        integrity: sha512-WOG+Jj8ZOvR0a3rAn+Tuf1UQJRxw5venr6DgdbJzngJE3qG7X0kL83CZGpdHMxEm+ZK3seAbvFsw4FfOfP9vxg==,
+        integrity: sha512-wLrXxPtcrPTsNlJmKjkPnNPK2Ihe0hn0wGSaTEiHRPxwjvJwT3hKmXF4dpqxmPO9SoNb2FsYXj/xEo0gHN+D5A==,
       }
 
   balanced-match@1.0.2:
@@ -3610,10 +3611,10 @@ packages:
       }
     engines: { node: '>= 0.4' }
 
-  postcss@8.5.8:
+  postcss@8.5.14:
     resolution:
       {
-        integrity: sha512-OW/rX8O/jXnm82Ey1k44pObPtdblfiuWnrd8X7GJ7emImCOstunGbXUpp7HdBrFQX6rJzn3sPT397Wp5aCwCHg==,
+        integrity: sha512-SoSL4+OSEtR99LHFZQiJLkT59C5B1amGO1NzTwj7TT1qCUgUO6hxOvzkOYxD+vMrXBM3XJIKzokoERdqQq/Zmg==,
       }
     engines: { node: ^10 || ^12 || >=14 }
 
@@ -5863,7 +5864,7 @@ snapshots:
     dependencies:
       possible-typed-array-names: 1.1.0
 
-  axios@1.15.1:
+  axios@1.15.2:
     dependencies:
       follow-redirects: 1.16.0
       form-data: 4.0.5
@@ -6914,7 +6915,7 @@ snapshots:
 
   possible-typed-array-names@1.1.0: {}
 
-  postcss@8.5.8:
+  postcss@8.5.14:
     dependencies:
       nanoid: 3.3.11
       picocolors: 1.1.1
@@ -7450,7 +7451,7 @@ snapshots:
       esbuild: 0.27.3
       fdir: 6.5.0(picomatch@4.0.4)
       picomatch: 4.0.4
-      postcss: 8.5.8
+      postcss: 8.5.14
       rollup: 4.59.0
       tinyglobby: 0.2.15
     optionalDependencies:
diff --git a/src/features/scan-url/api/uploadErrors.test.ts b/src/features/scan-url/api/uploadErrors.test.ts
index 15256c1..aa65ace 100644
--- a/src/features/scan-url/api/uploadErrors.test.ts
+++ b/src/features/scan-url/api/uploadErrors.test.ts
@@ -40,7 +40,7 @@ describe('isCaptchaRequiredUploadError', () => {
     expect(isCaptchaRequiredUploadError(error)).toBe(false);
   });
 
-  it('returns false for 429 responses without captcha markers', () => {
+  it('returns true for plain 429 upload responses', () => {
     const error = new ApiError({
       data: {
         message: 'Too many requests.',
@@ -49,6 +49,6 @@ describe('isCaptchaRequiredUploadError', () => {
       statusCode: 429,
     });
 
-    expect(isCaptchaRequiredUploadError(error)).toBe(false);
+    expect(isCaptchaRequiredUploadError(error)).toBe(true);
   });
 });
diff --git a/src/features/scan-url/api/uploadErrors.ts b/src/features/scan-url/api/uploadErrors.ts
index 10cd544..607cc21 100644
--- a/src/features/scan-url/api/uploadErrors.ts
+++ b/src/features/scan-url/api/uploadErrors.ts
@@ -1,26 +1,5 @@
 import { isApiError } from '@/shared/api/errors/apiError';
-import { pickString } from '@/shared/api/responseAccess/payloadAccess';
-
-function normalizeValue(value: string | null | undefined): string {
-  return value?.trim().toLowerCase() ?? '';
-}
 
 export function isCaptchaRequiredUploadError(error: unknown): boolean {
-  if (!isApiError(error) || error.statusCode !== 429) {
-    return false;
-  }
-
-  const errorCode = normalizeValue(
-    pickString(error.data, ['error_code', 'errorCode', 'code', 'status']),
-  );
-  const payloadMessage = pickString(error.data, [
-    'message',
-    'detail',
-    'error',
-    'error_description',
-    'description',
-  ]);
-  const message = normalizeValue([error.message, payloadMessage].filter(Boolean).join(' '));
-
-  return errorCode.includes('captcha') || message.includes('captcha') || message.includes('캡차');
+  return isApiError(error) && error.statusCode === 429;
 }
diff --git a/src/pages/QRScan/QRScanPage.tsx b/src/pages/QRScan/QRScanPage.tsx
index 517d3f7..61404c4 100644
--- a/src/pages/QRScan/QRScanPage.tsx
+++ b/src/pages/QRScan/QRScanPage.tsx
@@ -203,7 +203,12 @@ export default function QRScanPage() {
             {isCapturing ? '촬영 중...' : 'QR 스캔하기'}
           </button>
 
-          <button className={styles.secondaryButton} onClick={handleOpenGallery} type="button">
+          <button
+            className={styles.secondaryButton}
+            disabled={isCapturing}
+            onClick={handleOpenGallery}
+            type="button"
+          >
             <span aria-hidden className={styles.buttonIcon}>
               <UploadGlyphIcon />
             </span>
diff --git a/src/pages/QRScan/hooks/useQRScanPage.ts b/src/pages/QRScan/hooks/useQRScanPage.ts
index 21bc14f..5496636 100644
--- a/src/pages/QRScan/hooks/useQRScanPage.ts
+++ b/src/pages/QRScan/hooks/useQRScanPage.ts
@@ -177,6 +177,7 @@ export function useQRScanPage(): UseQRScanPageReturn {
   const latestPhotoUrlRef = useRef<string | null>(null);
   const flashTimerRef = useRef<number | null>(null);
   const isMountedRef = useRef(true);
+  const isScanSubmittingRef = useRef(false);
   const [cameraStatus, setCameraStatus] = useState<CameraStatus>('loading');
   const [cameraStatusText, setCameraStatusText] = useState('후면 카메라를 연결하는 중입니다.');
   const [captureRecord, setCaptureRecord] = useState<CaptureRecord | null>(null);
@@ -208,6 +209,24 @@ export function useQRScanPage(): UseQRScanPageReturn {
     setCaptureRecord(nextRecord);
   }, []);
 
+  const beginScanSubmission = useCallback(() => {
+    if (isScanSubmittingRef.current) {
+      return false;
+    }
+
+    isScanSubmittingRef.current = true;
+    setIsCapturing(true);
+    return true;
+  }, []);
+
+  const finishScanSubmission = useCallback(() => {
+    isScanSubmittingRef.current = false;
+
+    if (isMountedRef.current) {
+      setIsCapturing(false);
+    }
+  }, []);
+
   const startCamera = useCallback(async () => {
     if (typeof window === 'undefined' || typeof navigator === 'undefined') {
       return;
@@ -425,7 +444,9 @@ export function useQRScanPage(): UseQRScanPageReturn {
       return;
     }
 
-    setIsCapturing(true);
+    if (!beginScanSubmission()) {
+      return;
+    }
 
     try {
       const canvas = document.createElement('canvas');
@@ -471,12 +492,12 @@ export function useQRScanPage(): UseQRScanPageReturn {
       console.error('Failed to capture or upload QR scan image.', error);
       showApiError(message, error, 'QR 이미지 업로드에 실패했습니다.');
     } finally {
-      if (isMountedRef.current) {
-        setIsCapturing(false);
-      }
+      finishScanSubmission();
     }
   }, [
+    beginScanSubmission,
     cameraStatus,
+    finishScanSubmission,
     message,
     startCamera,
     submitScanFile,
@@ -485,8 +506,12 @@ export function useQRScanPage(): UseQRScanPageReturn {
   ]);
 
   const handleOpenGallery = useCallback(() => {
+    if (isCapturing) {
+      return;
+    }
+
     fileInputRef.current?.click();
-  }, []);
+  }, [isCapturing]);
 
   const handleGalleryFileChange = useCallback(
     (event: ChangeEvent<HTMLInputElement>) => {
@@ -496,36 +521,46 @@ export function useQRScanPage(): UseQRScanPageReturn {
         return;
       }
 
-      const photoUrl = URL.createObjectURL(selectedFile);
+      if (!beginScanSubmission()) {
+        event.target.value = '';
+        return;
+      }
 
-      updateCaptureRecord({
-        badgeLabel: 'UPLOAD',
-        capturedAt: formatCapturedAt(new Date()),
-        headline: selectedFile.name,
-        photoUrl,
-        summary: '갤러리 이미지를 불러와 최근 기록에 반영했습니다.',
-      });
+      let uploadStarted = false;
 
-      setIsCapturing(true);
+      try {
+        const photoUrl = URL.createObjectURL(selectedFile);
+
+        updateCaptureRecord({
+          badgeLabel: 'UPLOAD',
+          capturedAt: formatCapturedAt(new Date()),
+          headline: selectedFile.name,
+          photoUrl,
+          summary: '갤러리 이미지를 불러와 최근 기록에 반영했습니다.',
+        });
 
-      void submitScanFile({
-        file: selectedFile,
-        fileName: selectedFile.name,
-        onSuccessMessage: '이미지를 업로드하고 분석을 시작했습니다.',
-      })
-        .catch((error) => {
-          console.error('Failed to upload QR scan image from gallery.', error);
-          showApiError(message, error, '갤러리 이미지 업로드에 실패했습니다.');
+        void submitScanFile({
+          file: selectedFile,
+          fileName: selectedFile.name,
+          onSuccessMessage: '이미지를 업로드하고 분석을 시작했습니다.',
         })
-        .finally(() => {
-          if (isMountedRef.current) {
-            setIsCapturing(false);
-          }
-        });
+          .catch((error) => {
+            console.error('Failed to upload QR scan image from gallery.', error);
+            showApiError(message, error, '갤러리 이미지 업로드에 실패했습니다.');
+          })
+          .finally(() => {
+            finishScanSubmission();
+          });
 
-      event.target.value = '';
+        uploadStarted = true;
+        event.target.value = '';
+      } finally {
+        if (!uploadStarted) {
+          finishScanSubmission();
+        }
+      }
     },
-    [message, submitScanFile, updateCaptureRecord],
+    [beginScanSubmission, finishScanSubmission, message, submitScanFile, updateCaptureRecord],
   );
 
   return {
diff --git a/vercel.json b/vercel.json
index 6dafc4e..22835b4 100644
--- a/vercel.json
+++ b/vercel.json
@@ -2,11 +2,11 @@
   "rewrites": [
     {
       "source": "/be1/:path*",
-      "destination": "/api/be1?path=:path*"
+      "destination": "/api/be1/:path*"
     },
     {
       "source": "/be3/:path*",
-      "destination": "/api/be3?path=:path*"
+      "destination": "/api/be3/:path*"
     },
     {
       "source": "/(.*)",