diff --git a/src/app/api/auth/key-backup/route.js b/src/app/api/auth/key-backup/route.js
index 3b00161d..e6e7754c 100644
--- a/src/app/api/auth/key-backup/route.js
+++ b/src/app/api/auth/key-backup/route.js
@@ -17,6 +17,15 @@ function getServiceRoleClient() {
 // Create regular client for JWT validation
 const supabaseClient = createClient(process.env.NEXT_PUBLIC_SUPABASE_URL, process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY);
 
+function getBearerToken(authHeader) {
+	if (typeof authHeader !== 'string') return null;
+
+	const match = authHeader.match(/^Bearer\s+(.+)$/i);
+	const token = match?.[1]?.trim();
+
+	return token || null;
+}
+
 /**
  * Authenticate user from request cookies
  * @param {Request} request
@@ -26,8 +35,8 @@ async function authenticateUser(request) {
 	try {
 		// Try Authorization header first (used during login before cookies are set)
 		const authHeader = request.headers.get('authorization');
-		if (authHeader?.startsWith('Bearer ')) {
-			const token = authHeader.substring(7);
+		const token = getBearerToken(authHeader);
+		if (token) {
 			const { data: { user }, error } = await supabaseClient.auth.getUser(token);
 			if (!error && user) {
 				return { user };
diff --git a/src/app/api/auth/key-backup/route.test.js b/src/app/api/auth/key-backup/route.test.js
index c05d2644..4bed3cb0 100644
--- a/src/app/api/auth/key-backup/route.test.js
+++ b/src/app/api/auth/key-backup/route.test.js
@@ -79,4 +79,33 @@ describe('key backup cookie authentication', () => {
 		});
 		expect(mocks.authGetUser).toHaveBeenCalledWith('access-token');
 	});
+
+	it('normalizes bearer scheme casing and extra spaces', async () => {
+		const { GET } = await import('./route.js');
+		const response = await GET(
+			new Request('https://qrypt.chat/api/auth/key-backup', {
+				headers: {
+					authorization: 'bearer   access-token  '
+				}
+			})
+		);
+
+		expect(response.status).toBe(200);
+		expect(mocks.authGetUser).toHaveBeenCalledWith('access-token');
+	});
+
+	it('ignores an empty bearer header and falls back to cookies', async () => {
+		const { GET } = await import('./route.js');
+		const response = await GET(
+			new Request('https://qrypt.chat/api/auth/key-backup', {
+				headers: {
+					authorization: 'Bearer   ',
+					cookie: `sb-xydzwxwsbgmznthiiscl-auth-token=${cookieValue('cookie-token')}`
+				}
+			})
+		);
+
+		expect(response.status).toBe(200);
+		expect(mocks.authGetUser).toHaveBeenCalledWith('cookie-token');
+	});
 });