diff --git a/packages/javascript/src/errors/__tests__/ThunderIDAPIError.test.ts b/packages/javascript/src/errors/__tests__/ThunderIDAPIError.test.ts
index aa2d644..d8dc950 100644
--- a/packages/javascript/src/errors/__tests__/ThunderIDAPIError.test.ts
+++ b/packages/javascript/src/errors/__tests__/ThunderIDAPIError.test.ts
@@ -177,4 +177,20 @@ describe('ThunderIDAPIError — structured response body parsing', (): void => {
     const error: ThunderIDAPIError = new ThunderIDAPIError(errorText, 'CODE', 'javascript', 401);
     expect(error.message).toBe('Invalid credentials provided');
   });
+
+  it('should never surface a raw expired-flow response body to consumers', (): void => {
+    const errorText: string = JSON.stringify({
+      code: 'FES-1004',
+      description: {
+        defaultValue: 'Invalid flow execution ID provided in the request',
+        key: 'error.flowexecservice.invalid_execution_id_description',
+      },
+      message: {defaultValue: 'Invalid request', key: 'error.flowexecservice.invalid_execution_id'},
+    });
+    const error: ThunderIDAPIError = new ThunderIDAPIError(errorText, 'FES-1004', 'react', 400, 'Bad Request');
+
+    expect(error.message).not.toContain('FES-1004');
+    expect(error.message).not.toContain('error.flowexecservice');
+    expect(error.code).toBe('FES-1004');
+  });
 });
diff --git a/packages/react/src/components/presentation/auth/AcceptInvite/AcceptInvite.tsx b/packages/react/src/components/presentation/auth/AcceptInvite/AcceptInvite.tsx
index c2b23dd..e16dcb9 100644
--- a/packages/react/src/components/presentation/auth/AcceptInvite/AcceptInvite.tsx
+++ b/packages/react/src/components/presentation/auth/AcceptInvite/AcceptInvite.tsx
@@ -16,6 +16,7 @@
  * under the License.
  */
 
+import {ThunderIDAPIError} from '@thunderid/browser';
 import {FC, ReactElement, ReactNode, useMemo} from 'react';
 import BaseAcceptInvite, {BaseAcceptInviteRenderProps, AcceptInviteFlowResponse} from './BaseAcceptInvite';
 
@@ -189,7 +190,7 @@ const AcceptInvite: FC<AcceptInviteProps> = ({
    * Makes an unauthenticated request to /flow/execute endpoint.
    */
   const handleSubmit = async (payload: Record<string, any>): Promise<AcceptInviteFlowResponse> => {
-    const response: any = await fetch(`${apiBaseUrl}/flow/execute`, {
+    const response: Response = await fetch(`${apiBaseUrl}/flow/execute`, {
       body: JSON.stringify({
         ...payload,
         verbose: true,
@@ -202,8 +203,15 @@ const AcceptInvite: FC<AcceptInviteProps> = ({
     });
 
     if (!response.ok) {
-      const errorText: any = await response.text();
-      throw new Error(`Request failed: ${errorText}`);
+      const errorText: string = await response.text();
+      // ThunderIDAPIError resolves the raw API body into a readable message instead of leaking it.
+      throw new ThunderIDAPIError(
+        errorText,
+        'AcceptInvite-ResponseError-001',
+        'react',
+        response.status,
+        response.statusText,
+      );
     }
 
     return response.json();
diff --git a/packages/vue/src/components/presentation/accept-invite/AcceptInvite.ts b/packages/vue/src/components/presentation/accept-invite/AcceptInvite.ts
index 4413ea2..41c58e6 100644
--- a/packages/vue/src/components/presentation/accept-invite/AcceptInvite.ts
+++ b/packages/vue/src/components/presentation/accept-invite/AcceptInvite.ts
@@ -16,6 +16,7 @@
  * under the License.
  */
 
+import {ThunderIDAPIError} from '@thunderid/browser';
 import {type Component, type PropType, type SetupContext, type VNode, defineComponent, h} from 'vue';
 import BaseAcceptInvite from './BaseAcceptInvite';
 import type {AcceptInviteFlowResponse, BaseAcceptInviteRenderProps} from './BaseAcceptInvite';
@@ -78,7 +79,14 @@ const AcceptInvite: Component = defineComponent({
 
       if (!response.ok) {
         const errorText: string = await response.text();
-        throw new Error(`Request failed: ${errorText}`);
+        // ThunderIDAPIError resolves the raw API body into a readable message instead of leaking it.
+        throw new ThunderIDAPIError(
+          errorText,
+          'AcceptInvite-ResponseError-001',
+          'vue',
+          response.status,
+          response.statusText,
+        );
       }
 
       return response.json();