fix(api): reject custom_internal_name without consistent container naming

Container names use custom_internal_name only when consistent container
naming is on. The API accepted the name and then ignored it.

- Return 422 with a message that says to set
  is_consistent_container_name_enabled to true
- Accept the name when the request or the application turns the setting on
- Document the requirement in the OpenAPI spec

app/Http/Controllers/Api/ApplicationsController.php

@@ -183,6 +183,26 @@ class ApplicationsController extends Controller
         ], 422);
     }
 
+    /**
+     * Container names honor custom_internal_name only with consistent container naming, so reject a name that would be ignored.
+     */
+    private function customInternalNameValidationResponse(array $settings, ?Application $application = null): ?JsonResponse
+    {
+        if (! filled($settings['custom_internal_name'] ?? null)) {
+            return null;
+        }
+        $consistentNaming = $settings['is_consistent_container_name_enabled']
+            ?? (bool) $application?->settings?->is_consistent_container_name_enabled;
+        if ($consistentNaming) {
+            return null;
+        }
+
+        return response()->json([
+            'message' => 'Validation failed.',
+            'errors' => ['custom_internal_name' => ['Set is_consistent_container_name_enabled to true to use custom_internal_name. Coolify ignores the custom internal name while consistent container naming is turned off.']],
+        ], 422);
+    }
+
     private function applyApplicationSettings(Application $application, array $settings): void
     {
         if ($settings === []) {
@@ -419,7 +439,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -614,7 +634,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -809,7 +829,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -975,7 +995,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -1137,7 +1157,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -1391,6 +1411,9 @@ class ApplicationsController extends Controller
         if ($prefixValidation = $this->containerNamePrefixValidationResponse($applicationSettings, $destination->server)) {
             return $prefixValidation;
         }
+        if ($internalNameValidation = $this->customInternalNameValidationResponse($applicationSettings)) {
+            return $internalNameValidation;
+        }
         if ($type === 'public') {
             $validationRules = [
                 'git_repository' => ['string', 'required', new ValidGitRepositoryUrl],
@@ -3128,7 +3151,7 @@ class ApplicationsController extends Controller
                             'gpu_device_ids' => ['type' => 'string', 'nullable' => true, 'description' => 'Comma-separated GPU device IDs.'],
                             'gpu_options' => ['type' => 'string', 'nullable' => true, 'description' => 'Additional GPU options.'],
                             'is_consistent_container_name_enabled' => ['type' => 'boolean', 'description' => 'Use a consistent container name across deployments.'],
-                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name.'],
+                            'custom_internal_name' => ['type' => 'string', 'nullable' => true, 'description' => 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'],
                             'custom_container_name_prefix' => ['type' => 'string', 'nullable' => true, 'description' => 'Prefix for generated container names (prefix-20260908T141530). Slugified and unique across the instance.'],
                             'preview_url_template' => ['type' => 'string', 'description' => 'Preview URL template.'],
                             'max_restart_count' => ['type' => 'integer', 'minimum' => 0, 'description' => 'Maximum container restart count before stopping.'],
@@ -3312,6 +3335,9 @@ class ApplicationsController extends Controller
         if ($prefixValidation = $this->containerNamePrefixValidationResponse($applicationSettings, $application->destination->server, $application)) {
             return $prefixValidation;
         }
+        if ($internalNameValidation = $this->customInternalNameValidationResponse($applicationSettings, $application)) {
+            return $internalNameValidation;
+        }
         $requestedBuildPack = $request->input('build_pack', $application->build_pack);
         if (($applicationSettings['is_raw_compose_deployment_enabled'] ?? false) && $requestedBuildPack !== 'dockercompose') {
             return response()->json([

openapi.json

@@ -949,7 +949,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",
@@ -1540,7 +1540,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",
@@ -2131,7 +2131,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",
@@ -2617,7 +2617,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",
@@ -3083,7 +3083,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",
@@ -3794,7 +3794,7 @@
                                     "custom_internal_name": {
                                         "type": "string",
                                         "nullable": true,
-                                        "description": "Custom internal container name."
+                                        "description": "Custom internal container name. Requires is_consistent_container_name_enabled to be true."
                                     },
                                     "custom_container_name_prefix": {
                                         "type": "string",

openapi.yaml

@@ -622,7 +622,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true
@@ -1008,7 +1008,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true
@@ -1394,7 +1394,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true
@@ -1721,7 +1721,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true
@@ -2034,7 +2034,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true
@@ -2501,7 +2501,7 @@ paths:
                 custom_internal_name:
                   type: string
                   nullable: true
-                  description: 'Custom internal container name.'
+                  description: 'Custom internal container name. Requires is_consistent_container_name_enabled to be true.'
                 custom_container_name_prefix:
                   type: string
                   nullable: true

tests/Feature/Api/ApplicationCustomInternalNameConsistentNamingApiTest.php

@@ -0,0 +1,126 @@
+<?php
+
+use App\Models\Application;
+use App\Models\Environment;
+use App\Models\InstanceSettings;
+use App\Models\Project;
+use App\Models\Server;
+use App\Models\StandaloneDocker;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Queue;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    Server::flushIdentityMap();
+    config(['app.maintenance.store' => 'array']);
+    InstanceSettings::unguarded(fn () => InstanceSettings::firstOrCreate(['id' => 0]));
+
+    $this->team = Team::factory()->create();
+    $this->user = User::factory()->create();
+    $this->team->members()->attach($this->user->id, ['role' => 'owner']);
+    session(['currentTeam' => $this->team]);
+
+    $this->bearerToken = $this->user->createToken('custom-internal-name-test', ['*'])->plainTextToken;
+    $this->server = Server::factory()->create(['team_id' => $this->team->id]);
+    $this->destination = StandaloneDocker::where('server_id', $this->server->id)->first();
+    $this->project = Project::factory()->create(['team_id' => $this->team->id]);
+    $this->environment = Environment::factory()->create(['project_id' => $this->project->id]);
+    $this->application = Application::factory()->create([
+        'environment_id' => $this->environment->id,
+        'destination_id' => $this->destination->id,
+        'destination_type' => $this->destination->getMorphClass(),
+    ]);
+});
+
+function customInternalNameCreatePayload(array $overrides): array
+{
+    return array_merge([
+        'project_uuid' => test()->project->uuid,
+        'environment_uuid' => test()->environment->uuid,
+        'server_uuid' => test()->server->uuid,
+        'git_repository' => 'https://gitlab.com/coolify/custom-internal-name',
+        'git_branch' => 'main',
+        'build_pack' => 'nixpacks',
+        'ports_exposes' => '3000',
+        'autogenerate_domain' => false,
+    ], $overrides);
+}
+
+const CUSTOM_INTERNAL_NAME_NEEDS_CONSISTENT_NAMING = 'Set is_consistent_container_name_enabled to true to use custom_internal_name. Coolify ignores the custom internal name while consistent container naming is turned off.';
+
+test('updating only custom_internal_name is rejected while consistent container naming is off', function () {
+    $this->withToken($this->bearerToken)
+        ->patchJson("/api/v1/applications/{$this->application->uuid}", ['custom_internal_name' => 'my-app'])
+        ->assertUnprocessable()
+        ->assertJsonPath('errors.custom_internal_name.0', CUSTOM_INTERNAL_NAME_NEEDS_CONSISTENT_NAMING);
+
+    expect($this->application->fresh()->settings->custom_internal_name)->toBeNull();
+});
+
+test('updating custom_internal_name while turning consistent container naming off is rejected', function () {
+    $this->application->settings->update(['is_consistent_container_name_enabled' => true]);
+
+    $this->withToken($this->bearerToken)
+        ->patchJson("/api/v1/applications/{$this->application->uuid}", [
+            'custom_internal_name' => 'my-app',
+            'is_consistent_container_name_enabled' => false,
+        ])
+        ->assertUnprocessable()
+        ->assertJsonPath('errors.custom_internal_name.0', CUSTOM_INTERNAL_NAME_NEEDS_CONSISTENT_NAMING);
+});
+
+test('updating custom_internal_name together with consistent container naming succeeds', function () {
+    $this->withToken($this->bearerToken)
+        ->patchJson("/api/v1/applications/{$this->application->uuid}", [
+            'custom_internal_name' => 'my-app',
+            'is_consistent_container_name_enabled' => true,
+        ])
+        ->assertOk();
+
+    $settings = $this->application->fresh()->settings;
+    expect($settings->custom_internal_name)->toBe('my-app')
+        ->and($settings->is_consistent_container_name_enabled)->toBeTrue();
+});
+
+test('updating only custom_internal_name succeeds when consistent container naming is already on', function () {
+    $this->application->settings->update(['is_consistent_container_name_enabled' => true]);
+
+    $this->withToken($this->bearerToken)
+        ->patchJson("/api/v1/applications/{$this->application->uuid}", ['custom_internal_name' => 'my-app'])
+        ->assertOk();
+
+    expect($this->application->fresh()->settings->custom_internal_name)->toBe('my-app');
+});
+
+test('clearing custom_internal_name does not need consistent container naming', function (?string $value) {
+    $this->withToken($this->bearerToken)
+        ->patchJson("/api/v1/applications/{$this->application->uuid}", ['custom_internal_name' => $value])
+        ->assertOk();
+})->with(['null' => [null], 'empty string' => ['']]);
+
+test('creating an application with custom_internal_name requires consistent container naming', function () {
+    Queue::fake();
+
+    $this->withToken($this->bearerToken)
+        ->postJson('/api/v1/applications/public', customInternalNameCreatePayload(['custom_internal_name' => 'my-app']))
+        ->assertUnprocessable()
+        ->assertJsonPath('errors.custom_internal_name.0', CUSTOM_INTERNAL_NAME_NEEDS_CONSISTENT_NAMING);
+
+    expect(Application::query()->count())->toBe(1);
+});
+
+test('creating an application with custom_internal_name and consistent container naming succeeds', function () {
+    Queue::fake();
+
+    $response = $this->withToken($this->bearerToken)
+        ->postJson('/api/v1/applications/public', customInternalNameCreatePayload([
+            'custom_internal_name' => 'my-app',
+            'is_consistent_container_name_enabled' => true,
+        ]))
+        ->assertCreated();
+
+    expect(Application::query()->where('uuid', $response->json('uuid'))->sole()->settings->custom_internal_name)->toBe('my-app');
+});

tests/Feature/Api/ApplicationSettingsApiTest.php

@@ -351,6 +351,7 @@ test('PATCH /api/v1/applications/{uuid} accepts Docker-compatible custom interna
     $this->withHeaders(applicationSettingsApiHeaders($this->bearerToken))
         ->patchJson("/api/v1/applications/{$this->application->uuid}", [
             'custom_internal_name' => $name,
+            'is_consistent_container_name_enabled' => true,
         ])
         ->assertOk();