diff --git a/src/backend/src/modules/data-access/AppService.js b/src/backend/src/modules/data-access/AppService.js
index ae21a9d25..c08671a84 100644
--- a/src/backend/src/modules/data-access/AppService.js
+++ b/src/backend/src/modules/data-access/AppService.js
@@ -20,6 +20,12 @@ import {
     validate_url,
 } from './lib/validation.js';
 
+const APP_ICON_ENDPOINT_PATH_REGEX = /^\/?app-icon\/[^/?#]+\/[^/?#]+\/?$/;
+
+const isAppIconEndpointPath = (value) => {
+    return typeof value === 'string' && APP_ICON_ENDPOINT_PATH_REGEX.test(value);
+};
+
 /**
  * AppService contains an instance using the repository pattern
  */
@@ -385,6 +391,8 @@ export default class AppService extends BaseService {
             if ( object.icon !== undefined && object.icon !== null ) {
                 if ( typeof object.icon === 'string' && object.icon.startsWith('data:') ) {
                     validate_image_base64(object.icon, { key: 'icon' });
+                } else if ( isAppIconEndpointPath(object.icon) ) {
+                    // Allow existing relative app icon endpoint references.
                 } else {
                     validate_url(object.icon, { key: 'icon', maxlen: 3000 });
                 }
@@ -631,6 +639,8 @@ export default class AppService extends BaseService {
             if ( object.icon !== undefined && object.icon !== null ) {
                 if ( typeof object.icon === 'string' && object.icon.startsWith('data:') ) {
                     validate_image_base64(object.icon, { key: 'icon' });
+                } else if ( isAppIconEndpointPath(object.icon) ) {
+                    // Allow existing relative app icon endpoint references.
                 } else {
                     validate_url(object.icon, { key: 'icon', maxlen: 3000 });
                 }
diff --git a/src/backend/src/modules/data-access/AppService.test.js b/src/backend/src/modules/data-access/AppService.test.js
index 6915d1089..1157c95fd 100644
--- a/src/backend/src/modules/data-access/AppService.test.js
+++ b/src/backend/src/modules/data-access/AppService.test.js
@@ -806,6 +806,33 @@ describe('AppService', () => {
                             }));
         });
 
+        it('should allow relative app-icon endpoint path for icon', async () => {
+            setupContextForWrite(createMockUserActor(1));
+            mockDb.read.mockResolvedValue([createMockAppRow()]);
+            validate_url.mockImplementation((_value, { key }) => {
+                if ( key === 'icon' ) {
+                    throw new Error('icon should not be validated as a URL');
+                }
+            });
+
+            const crudQ = AppService.IMPLEMENTS['crud-q'];
+            await crudQ.create.call(appService, {
+                object: {
+                    name: 'test-app',
+                    title: 'Test',
+                    index_url: 'https://example.com',
+                    icon: '/app-icon/app-uid-123/64',
+                },
+            });
+
+            expect(mockEventService.emit).toHaveBeenCalledWith(
+                            'app.new-icon',
+                            expect.objectContaining({
+                                data_url: '/app-icon/app-uid-123/64',
+                            }));
+            expect(validate_url).toHaveBeenCalledWith('https://example.com', expect.objectContaining({ key: 'index_url' }));
+        });
+
         it('should handle filetype_associations', async () => {
             setupContextForWrite(createMockUserActor(1));
             mockDb.read.mockResolvedValue([createMockAppRow()]);
@@ -1060,6 +1087,30 @@ describe('AppService', () => {
                             }));
         });
 
+        it('should allow relative app-icon endpoint path when updating icon', async () => {
+            setupContextForWrite(createMockUserActor(1));
+            validate_url.mockImplementation((_value, { key }) => {
+                if ( key === 'icon' ) {
+                    throw new Error('icon should not be validated as a URL');
+                }
+            });
+
+            const crudQ = AppService.IMPLEMENTS['crud-q'];
+            await crudQ.update.call(appService, {
+                object: {
+                    uid: 'app-uid-123',
+                    icon: '/app-icon/app-uid-123/64',
+                },
+            });
+
+            expect(mockEventService.emit).toHaveBeenCalledWith(
+                            'app.new-icon',
+                            expect.objectContaining({
+                                app_uid: 'app-uid-123',
+                                data_url: '/app-icon/app-uid-123/64',
+                            }));
+        });
+
         it('should emit app.rename event when name changes', async () => {
             setupContextForWrite(createMockUserActor(1));