diff --git a/backend/.env b/backend/.env
index f2aa2ce..6a92cd9 100644
--- a/backend/.env
+++ b/backend/.env
@@ -51,6 +51,7 @@ REDIS_URL=redis://127.0.0.1:6380
 CONTACT_ENCRYPTION_KEY=change-me-encryption
 CONTACT_HASH_KEY=change-me-hash
 APP_DEFAULT_COUNTRY_CODE=+33
+SMS_PROVIDER=fake
 SMS_PROVIDER_TWILIO_ACCOUNT_SID=
 SMS_PROVIDER_TWILIO_AUTH_TOKEN=
 SMS_PROVIDER_TWILIO_FROM=
diff --git a/backend/.env.dev b/backend/.env.dev
index 9058a1c..03466c8 100644
--- a/backend/.env.dev
+++ b/backend/.env.dev
@@ -2,3 +2,4 @@
 ###> symfony/framework-bundle ###
 APP_SECRET=8a3935fa9a2fc896256979f4bd2780fc
 ###< symfony/framework-bundle ###
+SMS_PROVIDER=fake
diff --git a/backend/.env.test b/backend/.env.test
index 64bd111..c19339b 100644
--- a/backend/.env.test
+++ b/backend/.env.test
@@ -1,3 +1,4 @@
 # define your env variables for the test env here
 KERNEL_CLASS='App\Kernel'
 APP_SECRET='$ecretf0rt3st'
+SMS_PROVIDER=fake
diff --git a/backend/README.md b/backend/README.md
index 9067315..75ae278 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -231,6 +231,15 @@ Key local URLs:
 
 - API docs: `http://localhost:8002/docs`
 - Device/API endpoints: `http://localhost:8002/api/v1/...`
+- Fake SMS inbox in `dev`/`test`: `http://localhost:8002/debug/fake-sms`
+
+### Fake SMS in development
+
+- `SMS_PROVIDER=fake` is the default in `dev` and `test`.
+- The fake gateway writes messages to `backend/var/share/fake_sms_inbox.jsonl`.
+- You can inspect recent fake sends through `GET /debug/fake-sms`.
+- Production must override `SMS_PROVIDER=twilio` and provide real Twilio
+  credentials.
 
 ## Operational Notes
 
diff --git a/backend/config/packages/doctrine.yaml b/backend/config/packages/doctrine.yaml
index bec08a2..b96c178 100644
--- a/backend/config/packages/doctrine.yaml
+++ b/backend/config/packages/doctrine.yaml
@@ -6,8 +6,7 @@ doctrine:
         profiling_collect_backtrace: '%kernel.debug%'
         use_savepoints: true
     orm:
-        auto_generate_proxy_classes: true
-        enable_lazy_ghost_objects: true
+        enable_native_lazy_objects: true
         report_fields_where_declared: true
         validate_xml_mapping: true
         naming_strategy: doctrine.orm.naming_strategy.underscore_number_aware
@@ -33,8 +32,6 @@ when@test:
 when@prod:
     doctrine:
         orm:
-            auto_generate_proxy_classes: false
-            proxy_dir: '%kernel.build_dir%/doctrine/orm/Proxies'
             query_cache_driver:
                 type: pool
                 pool: doctrine.system_cache_pool
diff --git a/backend/config/services.yaml b/backend/config/services.yaml
index 0ee0c47..c88daef 100644
--- a/backend/config/services.yaml
+++ b/backend/config/services.yaml
@@ -7,9 +7,11 @@
 # Put parameters here that don't need to change on each machine where the app is deployed
 # https://symfony.com/doc/current/best_practices.html#use-parameters-for-application-configuration
 parameters:
+    app.share_dir: '%env(string:APP_SHARE_DIR)%'
     app.default_country_code: '%env(string:APP_DEFAULT_COUNTRY_CODE)%'
     app.contact_encryption_key: '%env(string:CONTACT_ENCRYPTION_KEY)%'
     app.contact_hash_key: '%env(string:CONTACT_HASH_KEY)%'
+    app.sms_provider: '%env(string:SMS_PROVIDER)%'
     app.twilio.account_sid: '%env(string:SMS_PROVIDER_TWILIO_ACCOUNT_SID)%'
     app.twilio.auth_token: '%env(string:SMS_PROVIDER_TWILIO_AUTH_TOKEN)%'
     app.twilio.from: '%env(string:SMS_PROVIDER_TWILIO_FROM)%'
@@ -34,10 +36,23 @@ services:
             $encryptionSecret: '%app.contact_encryption_key%'
             $hashSecret: '%app.contact_hash_key%'
 
+    App\Infrastructure\Sms\FakeSmsStore:
+        arguments:
+            $projectDir: '%kernel.project_dir%'
+            $shareDir: '%app.share_dir%'
+
     App\Infrastructure\Sms\TwilioSmsGateway:
         arguments:
             $accountSid: '%app.twilio.account_sid%'
             $authToken: '%app.twilio.auth_token%'
             $from: '%app.twilio.from%'
 
-    App\Application\SmsGateway: '@App\Infrastructure\Sms\TwilioSmsGateway'
+    App\Infrastructure\Sms\DelegatingSmsGateway:
+        arguments:
+            $provider: '%app.sms_provider%'
+
+    App\Controller\DebugFakeSmsController:
+        arguments:
+            $appEnv: '%kernel.environment%'
+
+    App\Application\SmsGateway: '@App\Infrastructure\Sms\DelegatingSmsGateway'
diff --git a/backend/src/Application/SmsGateway.php b/backend/src/Application/SmsGateway.php
index a2ff05a..6f30641 100644
--- a/backend/src/Application/SmsGateway.php
+++ b/backend/src/Application/SmsGateway.php
@@ -6,6 +6,8 @@
 
 interface SmsGateway
 {
+    public function getProviderName(): string;
+
     /** @return array{providerMessageId: ?string, status: string} */
     public function send(string $to, string $body): array;
 }
diff --git a/backend/src/Controller/DebugFakeSmsController.php b/backend/src/Controller/DebugFakeSmsController.php
new file mode 100644
index 0000000..36b301e
--- /dev/null
+++ b/backend/src/Controller/DebugFakeSmsController.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller;
+
+use App\Infrastructure\Sms\FakeSmsStore;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\Routing\Attribute\Route;
+
+final class DebugFakeSmsController
+{
+    public function __construct(
+        private readonly FakeSmsStore $store,
+        private readonly string $appEnv,
+    ) {
+    }
+
+    #[Route('/debug/fake-sms', name: 'app_debug_fake_sms', methods: ['GET'])]
+    public function __invoke(): JsonResponse
+    {
+        if ('prod' === $this->appEnv) {
+            throw new NotFoundHttpException();
+        }
+
+        return new JsonResponse([
+            'provider' => 'fake',
+            'messages' => $this->store->all(),
+        ]);
+    }
+}
diff --git a/backend/src/Infrastructure/Sms/DelegatingSmsGateway.php b/backend/src/Infrastructure/Sms/DelegatingSmsGateway.php
new file mode 100644
index 0000000..dae8b96
--- /dev/null
+++ b/backend/src/Infrastructure/Sms/DelegatingSmsGateway.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Infrastructure\Sms;
+
+use App\Application\SmsGateway;
+use InvalidArgumentException;
+
+use function sprintf;
+
+final class DelegatingSmsGateway implements SmsGateway
+{
+    public function __construct(
+        private readonly string $provider,
+        private readonly TwilioSmsGateway $twilioSmsGateway,
+        private readonly FakeSmsGateway $fakeSmsGateway,
+    ) {
+    }
+
+    public function getProviderName(): string
+    {
+        return $this->inner()->getProviderName();
+    }
+
+    public function send(string $to, string $body): array
+    {
+        return $this->inner()->send($to, $body);
+    }
+
+    private function inner(): SmsGateway
+    {
+        return match ($this->provider) {
+            'twilio' => $this->twilioSmsGateway,
+            'fake' => $this->fakeSmsGateway,
+            default => throw new InvalidArgumentException(sprintf('Unsupported SMS provider "%s".', $this->provider)),
+        };
+    }
+}
diff --git a/backend/src/Infrastructure/Sms/FakeSmsGateway.php b/backend/src/Infrastructure/Sms/FakeSmsGateway.php
new file mode 100644
index 0000000..c5bcea4
--- /dev/null
+++ b/backend/src/Infrastructure/Sms/FakeSmsGateway.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Infrastructure\Sms;
+
+use App\Application\SmsGateway;
+
+use function sprintf;
+
+use Symfony\Component\Uid\Uuid;
+
+final class FakeSmsGateway implements SmsGateway
+{
+    public function __construct(private readonly FakeSmsStore $store)
+    {
+    }
+
+    public function getProviderName(): string
+    {
+        return 'fake';
+    }
+
+    public function send(string $to, string $body): array
+    {
+        $providerMessageId = sprintf('fake-%s', Uuid::v7()->toRfc4122());
+        $this->store->append($providerMessageId, $to, $body);
+
+        return [
+            'providerMessageId' => $providerMessageId,
+            'status' => 'sent',
+        ];
+    }
+}
diff --git a/backend/src/Infrastructure/Sms/FakeSmsStore.php b/backend/src/Infrastructure/Sms/FakeSmsStore.php
new file mode 100644
index 0000000..5c78bcb
--- /dev/null
+++ b/backend/src/Infrastructure/Sms/FakeSmsStore.php
@@ -0,0 +1,112 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Infrastructure\Sms;
+
+use const DATE_ATOM;
+
+use DateTimeImmutable;
+
+use function dirname;
+use function explode;
+
+use const FILE_APPEND;
+
+use function file_exists;
+use function file_get_contents;
+use function file_put_contents;
+use function is_array;
+use function is_dir;
+use function is_string;
+use function json_decode;
+use function json_encode;
+
+use const JSON_THROW_ON_ERROR;
+
+use function mkdir;
+use function rtrim;
+use function sprintf;
+use function trim;
+
+final class FakeSmsStore
+{
+    public function __construct(
+        private readonly string $projectDir,
+        private readonly string $shareDir,
+    ) {
+    }
+
+    /**
+     * @return array<int, array{providerMessageId: string, to: string, body: string, createdAt: string}>
+     */
+    public function all(): array
+    {
+        $path = $this->path();
+
+        if (!file_exists($path)) {
+            return [];
+        }
+
+        $entries = [];
+        $contents = file_get_contents($path);
+
+        if (false === $contents || '' === $contents) {
+            return [];
+        }
+
+        foreach (explode("\n", trim($contents)) as $line) {
+            if ('' === $line) {
+                continue;
+            }
+
+            $decoded = json_decode($line, true, 512, JSON_THROW_ON_ERROR);
+
+            if (
+                is_array($decoded)
+                && isset($decoded['providerMessageId'], $decoded['to'], $decoded['body'], $decoded['createdAt'])
+                && is_string($decoded['providerMessageId'])
+                && is_string($decoded['to'])
+                && is_string($decoded['body'])
+                && is_string($decoded['createdAt'])
+            ) {
+                /* @var array{providerMessageId: string, to: string, body: string, createdAt: string} $decoded */
+                $entries[] = $decoded;
+            }
+        }
+
+        return $entries;
+    }
+
+    public function append(string $providerMessageId, string $to, string $body): void
+    {
+        $path = $this->path();
+        $directory = dirname($path);
+
+        if (!is_dir($directory)) {
+            mkdir($directory, 0777, true);
+        }
+
+        $entry = [
+            'providerMessageId' => $providerMessageId,
+            'to' => $to,
+            'body' => $body,
+            'createdAt' => (new DateTimeImmutable())->format(DATE_ATOM),
+        ];
+
+        file_put_contents(
+            $path,
+            sprintf("%s\n", json_encode($entry, JSON_THROW_ON_ERROR)),
+            FILE_APPEND,
+        );
+    }
+
+    private function path(): string
+    {
+        return sprintf(
+            '%s/%s/fake_sms_inbox.jsonl',
+            $this->projectDir,
+            rtrim($this->shareDir, '/'),
+        );
+    }
+}
diff --git a/backend/src/Infrastructure/Sms/TwilioSmsGateway.php b/backend/src/Infrastructure/Sms/TwilioSmsGateway.php
index e23151d..1ac5765 100644
--- a/backend/src/Infrastructure/Sms/TwilioSmsGateway.php
+++ b/backend/src/Infrastructure/Sms/TwilioSmsGateway.php
@@ -17,6 +17,11 @@ public function __construct(
     ) {
     }
 
+    public function getProviderName(): string
+    {
+        return 'twilio';
+    }
+
     public function send(string $to, string $body): array
     {
         if ('' === $this->accountSid || '' === $this->authToken || '' === $this->from) {
diff --git a/backend/src/MessageHandler/SendFallAlertMessageHandler.php b/backend/src/MessageHandler/SendFallAlertMessageHandler.php
index dd55156..347bbdd 100644
--- a/backend/src/MessageHandler/SendFallAlertMessageHandler.php
+++ b/backend/src/MessageHandler/SendFallAlertMessageHandler.php
@@ -51,8 +51,9 @@ public function __invoke(SendFallAlertMessage $message): void
         }
 
         $sentCount = 0;
+        $provider = $this->smsGateway->getProviderName();
         foreach ($contacts as $contact) {
-            $attempt = new SmsAttempt($alert, $contact, 'twilio');
+            $attempt = new SmsAttempt($alert, $contact, $provider);
             $alert->addSmsAttempt($attempt);
             $this->entityManager->persist($attempt);
 
diff --git a/backend/tests/Integration/Api/DebugFakeSmsControllerTest.php b/backend/tests/Integration/Api/DebugFakeSmsControllerTest.php
new file mode 100644
index 0000000..3231254
--- /dev/null
+++ b/backend/tests/Integration/Api/DebugFakeSmsControllerTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Integration\Api;
+
+use App\Infrastructure\Sms\FakeSmsGateway;
+
+use function json_decode;
+
+use const JSON_THROW_ON_ERROR;
+
+use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
+
+final class DebugFakeSmsControllerTest extends WebTestCase
+{
+    public function testFakeSmsInboxEndpointReturnsStoredMessages(): void
+    {
+        $client = static::createClient();
+        $gateway = self::getContainer()->get(FakeSmsGateway::class);
+        $gateway->send('+33612345678', 'Hello fake SMS');
+
+        $client->request('GET', '/debug/fake-sms');
+
+        self::assertResponseIsSuccessful();
+
+        /** @var array{provider?: string, messages?: list<array{to?: string, body?: string}>} $payload */
+        $payload = json_decode($client->getResponse()->getContent() ?: '', true, 512, JSON_THROW_ON_ERROR);
+
+        self::assertSame('fake', $payload['provider'] ?? null);
+        self::assertCount(1, $payload['messages'] ?? []);
+        self::assertSame('+33612345678', $payload['messages'][0]['to'] ?? null);
+        self::assertSame('Hello fake SMS', $payload['messages'][0]['body'] ?? null);
+    }
+}
diff --git a/backend/tests/Unit/Infrastructure/FakeSmsGatewayTest.php b/backend/tests/Unit/Infrastructure/FakeSmsGatewayTest.php
new file mode 100644
index 0000000..c3652b8
--- /dev/null
+++ b/backend/tests/Unit/Infrastructure/FakeSmsGatewayTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Infrastructure;
+
+use App\Infrastructure\Sms\FakeSmsGateway;
+use App\Infrastructure\Sms\FakeSmsStore;
+use PHPUnit\Framework\TestCase;
+
+use function sys_get_temp_dir;
+use function uniqid;
+
+final class FakeSmsGatewayTest extends TestCase
+{
+    public function testItStoresOutgoingMessagesInTheFakeInbox(): void
+    {
+        $root = sys_get_temp_dir() . '/fall_guardian_fake_sms_' . uniqid('', true);
+        $store = new FakeSmsStore($root, 'var/share');
+        $gateway = new FakeSmsGateway($store);
+
+        $result = $gateway->send('+33612345678', 'Test message');
+
+        self::assertSame('fake', $gateway->getProviderName());
+        self::assertSame('sent', $result['status']);
+        self::assertStringStartsWith('fake-', (string) $result['providerMessageId']);
+
+        $entries = $store->all();
+
+        self::assertCount(1, $entries);
+        self::assertSame('+33612345678', $entries[0]['to']);
+        self::assertSame('Test message', $entries[0]['body']);
+        self::assertSame($result['providerMessageId'], $entries[0]['providerMessageId']);
+    }
+}