diff --git a/CHANGELOG.md b/CHANGELOG.md
index 197745d..f5c83f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,17 @@ may contain breaking changes; read the **Upgrading** notes before bumping a mino
 
 ## [Unreleased]
 
+## [0.13.1] - 2026-09-06
+
+### Fixed
+
+- Requests are validated against the OpenAPI document of **their own** Nelmio area. Previously every
+  request was validated against the `default` area's document, while route detection accepted a route
+  belonging to any area — so in a multi-area application a valid request to a non-default area was
+  rejected with a `400` `openapi_request_validation`. Single-area applications are unaffected.
+- An area whose name is numeric (`2024`) no longer raises a `TypeError` during route lookup. PHP stores
+  such a key as an `int`, which `ServiceLocator::get(string $id)` rejects under `strict_types`.
+
 ## [0.12.4] - 2026-08-30
 
 Documentation only — no code changes since `0.12.3`.
@@ -208,7 +219,8 @@ Installing it with Composer is not enough. See the README's installation section
   details outside debug mode, and a `CommandValueResolver` that supports list endpoints and the combination of
   parameters with a request body.
 
-[Unreleased]: https://github.com/stixx/openapi-command-bundle/compare/0.12.4...HEAD
+[Unreleased]: https://github.com/stixx/openapi-command-bundle/compare/0.13.1...HEAD
+[0.13.1]: https://github.com/stixx/openapi-command-bundle/compare/0.13.0...0.13.1
 [0.12.4]: https://github.com/stixx/openapi-command-bundle/compare/0.12.3...0.12.4
 [0.12.3]: https://github.com/stixx/openapi-command-bundle/compare/0.12.2...0.12.3
 [0.12.2]: https://github.com/stixx/openapi-command-bundle/compare/0.12.1...0.12.2
diff --git a/config/validators.php b/config/validators.php
index c7083e6..e3e925c 100644
--- a/config/validators.php
+++ b/config/validators.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Nyholm\Psr7\Factory\Psr17Factory;
+use Stixx\OpenApiCommandBundle\Routing\NelmioAreaRoutesChecker;
 use Stixx\OpenApiCommandBundle\Validator\RequestValidator;
 use Stixx\OpenApiCommandBundle\Validator\RequestValidatorChain;
 use Stixx\OpenApiCommandBundle\Validator\ValidatorInterface as StixxValidatorInterface;
@@ -37,5 +38,7 @@
         ->set(RequestValidator::class)
             ->arg('$apiDocGenerator', service('nelmio_api_doc.generator.default'))
             ->arg('$psrHttpFactory', service('stixx_openapi_command.psr_http_factory'))
+            ->arg('$generatorsLocator', service('stixx_openapi_command.nelmio.generators_locator'))
+            ->arg('$areaRoutesChecker', service(NelmioAreaRoutesChecker::class))
             ->tag(StixxValidatorInterface::TAG_NAME);
 };
diff --git a/docs/validation.md b/docs/validation.md
index 3b9b26e..0e29beb 100644
--- a/docs/validation.md
+++ b/docs/validation.md
@@ -161,6 +161,8 @@ services:
 
 All tagged validators are executed in a chain during the `kernel.request` event, but only for routes that are managed by this bundle (detected via `NelmioAreaRoutesChecker`). If any validator throws an exception, the request cycle is interrupted.
 
+When several Nelmio areas are configured, each has its own OpenAPI document. `NelmioAreaRoutesChecker` resolves the area a request belongs to, and the request is validated against that area's document. Areas are checked in registration order and the first match wins.
+
 ---
 
 ## Customizing Error Responses
diff --git a/src/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPass.php b/src/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPass.php
index 963d1e9..bfae883 100644
--- a/src/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPass.php
+++ b/src/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPass.php
@@ -36,6 +36,8 @@ public function process(ContainerBuilder $container): void
         $routesMap = [];
         $pathPatterns = [];
 
+        $generatorsMap = [];
+
         foreach ($areas as $area) {
             $serviceId = sprintf('nelmio_api_doc.routes.%s', $area);
 
@@ -45,6 +47,11 @@ public function process(ContainerBuilder $container): void
 
             $routesMap[$area] = new Reference($serviceId);
             $pathPatterns[$area] = $this->extractPathPatterns($container, $serviceId);
+
+            $generatorId = sprintf('nelmio_api_doc.generator.%s', $area);
+            if ($container->has($generatorId)) {
+                $generatorsMap[$area] = new Reference($generatorId);
+            }
         }
 
         $container->register('stixx_openapi_command.nelmio.routes_locator', ServiceLocator::class)
@@ -52,6 +59,11 @@ public function process(ContainerBuilder $container): void
             ->setPublic(false)
             ->setArguments([$routesMap]);
 
+        $container->register('stixx_openapi_command.nelmio.generators_locator', ServiceLocator::class)
+            ->addTag('container.service_locator')
+            ->setPublic(false)
+            ->setArguments([$generatorsMap]);
+
         $container->setParameter('stixx_openapi_command.nelmio.path_patterns', $pathPatterns);
     }
 
diff --git a/src/Routing/NelmioAreaRoutesChecker.php b/src/Routing/NelmioAreaRoutesChecker.php
index cf3cbf5..4867369 100644
--- a/src/Routing/NelmioAreaRoutesChecker.php
+++ b/src/Routing/NelmioAreaRoutesChecker.php
@@ -33,10 +33,21 @@ public function __construct(
     }
 
     public function isApiRoute(Request $request): bool
+    {
+        return null !== $this->areaFor($request);
+    }
+
+    /**
+     * The Nelmio area a request belongs to, or null if none. Areas are checked in registration order.
+     */
+    public function areaFor(Request $request): ?string
     {
         $routeName = $request->attributes->get('_route', '');
-        if (is_string($routeName) && $routeName !== '' && $this->matchesByRouteName($routeName)) {
-            return true;
+        if (is_string($routeName) && $routeName !== '') {
+            $area = $this->matchesByRouteName($routeName);
+            if (null !== $area) {
+                return $area;
+            }
         }
 
         // Symfony does not set _route when the path doesn't match any route (404) or when no method
@@ -45,32 +56,32 @@ public function isApiRoute(Request $request): bool
         return $this->matchesByPath($request->getPathInfo());
     }
 
-    private function matchesByRouteName(string $routeName): bool
+    private function matchesByRouteName(string $routeName): ?string
     {
         foreach (array_keys($this->routesLocator->getProvidedServices()) as $area) {
-            $routeCollection = $this->routesLocator->get($area);
+            $routeCollection = $this->routesLocator->get((string) $area);
             if (!$routeCollection instanceof RouteCollection) {
                 continue;
             }
 
             if (null !== $routeCollection->get($routeName)) {
-                return true;
+                return (string) $area;
             }
         }
 
-        return false;
+        return null;
     }
 
-    private function matchesByPath(string $path): bool
+    private function matchesByPath(string $path): ?string
     {
-        foreach ($this->pathPatterns as $patterns) {
+        foreach ($this->pathPatterns as $area => $patterns) {
             foreach ($patterns as $pattern) {
                 if (preg_match('{'.$pattern.'}', $path) === 1) {
-                    return true;
+                    return (string) $area;
                 }
             }
         }
 
-        return false;
+        return null;
     }
 }
diff --git a/src/Validator/RequestValidator.php b/src/Validator/RequestValidator.php
index efabd5f..d87a7ce 100644
--- a/src/Validator/RequestValidator.php
+++ b/src/Validator/RequestValidator.php
@@ -16,7 +16,9 @@
 use League\OpenAPIValidation\PSR7\RequestValidator as OpenApiRequestValidator;
 use League\OpenAPIValidation\PSR7\ValidatorBuilder;
 use Nelmio\ApiDocBundle\ApiDocGenerator;
+use Stixx\OpenApiCommandBundle\Routing\NelmioAreaRoutesChecker;
 use Symfony\Bridge\PsrHttpMessage\HttpMessageFactoryInterface;
+use Symfony\Component\DependencyInjection\ServiceLocator;
 use Symfony\Component\HttpFoundation\Request;
 
 /**
@@ -24,28 +26,45 @@
  */
 final class RequestValidator implements ValidatorInterface
 {
-    private ?OpenApiRequestValidator $cachedValidator = null;
+    /** @var array<string, OpenApiRequestValidator> */
+    private array $cachedValidators = [];
 
+    /**
+     * @param ServiceLocator<ApiDocGenerator>|null $generatorsLocator
+     */
     public function __construct(
         private readonly ApiDocGenerator $apiDocGenerator,
         private readonly HttpMessageFactoryInterface $psrHttpFactory,
+        private readonly ?ServiceLocator $generatorsLocator = null,
+        private readonly ?NelmioAreaRoutesChecker $areaRoutesChecker = null,
     ) {
     }
 
     public function validate(Request $request): void
     {
         $psrRequest = $this->psrHttpFactory->createRequest($request);
-        $this->getValidator()->validate($psrRequest);
+        $this->getValidator($this->areaFor($request))->validate($psrRequest);
     }
 
-    private function getValidator(): OpenApiRequestValidator
+    private function areaFor(Request $request): string
     {
-        if ($this->cachedValidator !== null) {
-            return $this->cachedValidator;
+        return $this->areaRoutesChecker?->areaFor($request) ?? 'default';
+    }
+
+    private function getValidator(string $area): OpenApiRequestValidator
+    {
+        if (isset($this->cachedValidators[$area])) {
+            return $this->cachedValidators[$area];
         }
 
-        $apiDoc = $this->apiDocGenerator->generate();
+        $generator = $this->generatorsLocator?->has($area) === true
+            ? $this->generatorsLocator->get($area)
+            : $this->apiDocGenerator;
+
+        $apiDoc = $generator->generate();
 
-        return $this->cachedValidator = new ValidatorBuilder()->fromJson($apiDoc->toJson())->getRequestValidator();
+        return $this->cachedValidators[$area] = new ValidatorBuilder()
+            ->fromJson($apiDoc->toJson())
+            ->getRequestValidator();
     }
 }
diff --git a/tests/Unit/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPassTest.php b/tests/Unit/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPassTest.php
index 9582b8d..41eb9f0 100644
--- a/tests/Unit/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPassTest.php
+++ b/tests/Unit/DependencyInjection/Compiler/CollectNelmioApiDocRoutesPassTest.php
@@ -39,6 +39,8 @@ public function testProcessWithAreas(): void
         $container->setDefinition('nelmio_api_doc.routes.default', new Definition(stdClass::class));
         // 'nelmio_api_doc.routes.internal' is missing on purpose — it should be skipped silently.
 
+        $container->setDefinition('nelmio_api_doc.generator.default', new Definition(stdClass::class));
+
         $pass = new CollectNelmioApiDocRoutesPass();
 
         // Act
@@ -56,6 +58,17 @@ public function testProcessWithAreas(): void
         ];
         self::assertEquals([$expectedMap], $definition->getArguments());
 
+        self::assertTrue($container->hasDefinition('stixx_openapi_command.nelmio.generators_locator'));
+        $generatorsDefinition = $container->getDefinition('stixx_openapi_command.nelmio.generators_locator');
+
+        self::assertSame(ServiceLocator::class, $generatorsDefinition->getClass());
+        self::assertTrue($generatorsDefinition->hasTag('container.service_locator'));
+
+        $expectedGeneratorsMap = [
+            'default' => new Reference('nelmio_api_doc.generator.default'),
+        ];
+        self::assertEquals([$expectedGeneratorsMap], $generatorsDefinition->getArguments());
+
         self::assertTrue($container->hasParameter('stixx_openapi_command.nelmio.path_patterns'));
         self::assertSame(
             ['default' => []],
diff --git a/tests/Unit/Validator/RequestValidatorTest.php b/tests/Unit/Validator/RequestValidatorTest.php
index fccbf73..325f3b6 100644
--- a/tests/Unit/Validator/RequestValidatorTest.php
+++ b/tests/Unit/Validator/RequestValidatorTest.php
@@ -26,9 +26,13 @@
 use OpenApi\Annotations\Schema;
 use OpenApi\Context;
 use PHPUnit\Framework\TestCase;
+use Stixx\OpenApiCommandBundle\Routing\NelmioAreaRoutesChecker;
 use Stixx\OpenApiCommandBundle\Validator\RequestValidator;
 use Symfony\Bridge\PsrHttpMessage\Factory\PsrHttpFactory;
+use Symfony\Component\DependencyInjection\ServiceLocator;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Route;
+use Symfony\Component\Routing\RouteCollection;
 
 final class RequestValidatorTest extends TestCase
 {
@@ -109,6 +113,56 @@ public function describe(OpenApi $api): void
         self::assertSame(1, $describer->describeCalls);
     }
 
+    public function testValidatesAgainstTheRequestsOwnAreaNotTheDefaultArea(): void
+    {
+        // Arrange
+        $defaultGenerator = new ApiDocGenerator([$this->createDescriberForPath('/default')], []);
+        $internalGenerator = new ApiDocGenerator([$this->createDescriberForPath('/internal')], []);
+
+        $request = Request::create('/internal', 'POST');
+        $request->attributes->set('_route', 'internal_route');
+
+        $validator = new RequestValidator(
+            $defaultGenerator,
+            $this->createPsrHttpFactory(),
+            $this->createGeneratorsLocator($defaultGenerator, $internalGenerator),
+            $this->createAreaChecker(['default' => '/default', 'internal' => '/internal']),
+        );
+
+        // Act
+        $validator->validate($request);
+
+        // Assert: /internal exists only in the internal area's document; the default document would raise NoPath.
+        $this->expectNotToPerformAssertions();
+    }
+
+    public function testKeepsASeparateValidatorPerArea(): void
+    {
+        // Arrange
+        $defaultGenerator = new ApiDocGenerator([$this->createDescriberForPath('/default')], []);
+        $internalGenerator = new ApiDocGenerator([$this->createDescriberForPath('/internal')], []);
+
+        $validator = new RequestValidator(
+            $defaultGenerator,
+            $this->createPsrHttpFactory(),
+            $this->createGeneratorsLocator($defaultGenerator, $internalGenerator),
+            $this->createAreaChecker(['default' => '/default', 'internal' => '/internal']),
+        );
+
+        $internal = Request::create('/internal', 'POST');
+        $internal->attributes->set('_route', 'internal_route');
+
+        $default = Request::create('/default', 'POST');
+        $default->attributes->set('_route', 'default_route');
+
+        // Act: the internal area first, so its validator is memoised before the default area is used.
+        $validator->validate($internal);
+        $validator->validate($default);
+
+        // Assert: a shared memo would validate /default against the internal document and raise NoPath.
+        $this->expectNotToPerformAssertions();
+    }
+
     private function createPsrHttpFactory(): PsrHttpFactory
     {
         $psr17 = new Psr17Factory();
@@ -149,4 +203,58 @@ public function describe(OpenApi $api): void
             }
         };
     }
+
+    private function createDescriberForPath(string $path): DescriberInterface
+    {
+        return new class ($path) implements DescriberInterface {
+            public function __construct(private readonly string $path)
+            {
+            }
+
+            public function describe(OpenApi $api): void
+            {
+                $api->info = new Info(['title' => 'Test', 'version' => '1.0.0', '_context' => new Context(['version' => '3.0.0'], null)]);
+                $api->paths = [
+                    new PathItem([
+                        'path' => $this->path,
+                        'post' => new Post([
+                            'responses' => [new Response(['response' => 200, 'description' => 'ok', '_context' => new Context(['version' => '3.0.0'], null)])],
+                            '_context' => new Context(['version' => '3.0.0'], null),
+                        ]),
+                        '_context' => new Context(['version' => '3.0.0'], null),
+                    ]),
+                ];
+            }
+        };
+    }
+
+    /** @return ServiceLocator<ApiDocGenerator> */
+    private function createGeneratorsLocator(ApiDocGenerator $default, ApiDocGenerator $internal): ServiceLocator
+    {
+        /** @var ServiceLocator<ApiDocGenerator> $locator */
+        $locator = new ServiceLocator([
+            'default' => static fn (): ApiDocGenerator => $default,
+            'internal' => static fn (): ApiDocGenerator => $internal,
+        ]);
+
+        return $locator;
+    }
+
+    /** @param array<string, string> $areaToPath */
+    private function createAreaChecker(array $areaToPath): NelmioAreaRoutesChecker
+    {
+        $routes = [];
+        $patterns = [];
+        foreach ($areaToPath as $area => $path) {
+            $collection = new RouteCollection();
+            $collection->add($area.'_route', new Route($path));
+            $routes[$area] = static fn (): RouteCollection => $collection;
+            $patterns[$area] = ['^'.preg_quote($path, '{}')];
+        }
+
+        /** @var ServiceLocator<RouteCollection> $locator */
+        $locator = new ServiceLocator($routes);
+
+        return new NelmioAreaRoutesChecker($locator, $patterns);
+    }
 }