diff --git a/resources/js/Pages/Endpoints/Index.vue b/resources/js/Pages/Endpoints/Index.vue
index 93e0f75..e4ecdb8 100644
--- a/resources/js/Pages/Endpoints/Index.vue
+++ b/resources/js/Pages/Endpoints/Index.vue
@@ -415,7 +415,19 @@ async function saveEndpoint() {
             showOneTimeSecret(response.data.plain_secret)
         } catch (error) {
             if (error.response?.data?.errors) {
-                form.setError(error.response.data.errors)
+                // Laravel's JSON validation-error response shapes each field
+                // as an array of messages. A normal Inertia form submission
+                // flattens these before they reach the client, but this is a
+                // raw axios call, so it must be flattened here too — otherwise
+                // form.setError() stores the array itself and InputError.vue
+                // (which expects a string) renders it as a JSON blob.
+                const errors = Object.fromEntries(
+                    Object.entries(error.response.data.errors).map(([field, messages]) => [
+                        field,
+                        Array.isArray(messages) ? messages[0] : messages,
+                    ])
+                )
+                form.setError(errors)
             } else {
                 alert('Failed to save endpoint. Please try again.')
             }
diff --git a/tests/Feature/EndpointCreateValidationErrorFormatTest.php b/tests/Feature/EndpointCreateValidationErrorFormatTest.php
new file mode 100644
index 0000000..03bc097
--- /dev/null
+++ b/tests/Feature/EndpointCreateValidationErrorFormatTest.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class EndpointCreateValidationErrorFormatTest extends TestCase
+{
+    use RefreshDatabase;
+
+    /**
+     * The "Create Endpoint" modal submits via a raw axios call (rather than
+     * Inertia's form helper) so it can read back the one-time plain_secret
+     * on success, which means the frontend receives Laravel's raw JSON
+     * validation-error shape and must flatten it itself. This test pins
+     * that shape down: each field's errors are an array of messages, not a
+     * single string.
+     */
+    public function test_validation_errors_for_ajax_endpoint_creation_are_returned_as_arrays_per_field(): void
+    {
+        $user = User::factory()->withPersonalTeam()->create();
+
+        $response = $this->actingAs($user)->postJson('/endpoints', [
+            'name' => '',
+            'url' => 'not-a-url',
+        ]);
+
+        $response->assertStatus(422);
+        $response->assertJsonValidationErrors(['name', 'url']);
+        $this->assertIsArray($response->json('errors.name'));
+        $this->assertIsArray($response->json('errors.url'));
+    }
+}