diff --git a/app/Http/Controllers/Api/V1/CustomerController.php b/app/Http/Controllers/Api/V1/CustomerController.php
index 7bee493..a46b8c1 100644
--- a/app/Http/Controllers/Api/V1/CustomerController.php
+++ b/app/Http/Controllers/Api/V1/CustomerController.php
@@ -60,20 +60,24 @@ class CustomerController extends Controller
             $customer        = new Customer();
             $customer->email = $email;
             $customer->save();
-            $singleOptin = SingleOptin::where([['email', $email], ['brand_id', $brandId]])->first();
+            $singleOptin = SingleOptin::query()->where([
+                ['email', $email], ['brand_id', $brandId]
+            ])->first();
             if ($singleOptin) {
                 $singleOptin->delete();
             }
         } else {
             // Récupère les infos s'ils existent déjà.
-            $CustomerInfo = CustomerInfo::where([['customer_id', $customer->id], ['brand_id', $brandId]])->first();
+            $CustomerInfo = CustomerInfo::query()->where([
+                ['customer_id', $customer->id], ['brand_id', $brandId]
+            ])->first();
             if ($CustomerInfo) {
                 return new StatusResource([
                     'status' => 'KO', 'code' => 103,
                     'message' => 'User already registered on this site.'
                 ]);
             }
-        }
+        }//end if
 
         $customerInfos             = new CustomerInfo();
         $customerInfos->firstname  = ucfirst(strtolower($firstname));
@@ -549,7 +553,7 @@ class CustomerController extends Controller
 
         // Check si le customer ou l'optin simple existe avant de l'ajouter en optin simple.
         if (
-            !SingleOptin::where([['email', $email], ['brand_id', $brandId]])->exists() &&
+            !SingleOptin::query()->where([['email', $email], ['brand_id', $brandId]])->exists() &&
             !CustomerInfo::join("customers", "customer_infos.customer_id", "=", "customers.id")->where([
                 ['brand_id', $brandId], ['email', $email]
             ])->exists()
diff --git a/app/Http/Controllers/Api/V2/CustomerController.php b/app/Http/Controllers/Api/V2/CustomerController.php
index 9ebbe2f..09368b4 100644
--- a/app/Http/Controllers/Api/V2/CustomerController.php
+++ b/app/Http/Controllers/Api/V2/CustomerController.php
@@ -14,6 +14,7 @@ use App\Jobs\UpdateCustomerLastConnection;
 use App\Models\Customer;
 use App\Models\Service;
 use App\Models\SingleOptin;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\ModelNotFoundException;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Resources\Json\JsonResource;
@@ -47,8 +48,10 @@ class CustomerController extends Controller
 
             // * Delete Single optin if exists.
             /** @var \App\Models\SingleOptin|null $singleOptin */
-            $singleOptin = SingleOptin::where('email', $data->email)
-                ->where('brand_id', $service->brand->id)->first();
+            $singleOptin = SingleOptin::query()->where('email', $data->email)
+                ->whereHas('brand', function (Builder $q) use ($service) {
+                    $q->where('id', $service->brand->id);
+                })->first();
             if ($singleOptin) {
                 $saved = $singleOptin->delete() && $saved;
             }
diff --git a/app/Http/Controllers/Api/V2/OptinController.php b/app/Http/Controllers/Api/V2/OptinController.php
index edfe4ca..d5c8415 100644
--- a/app/Http/Controllers/Api/V2/OptinController.php
+++ b/app/Http/Controllers/Api/V2/OptinController.php
@@ -31,9 +31,9 @@ class OptinController extends Controller
         }
 
         /** @var \App\Models\SingleOptin */
-        $singleOptin = SingleOptin::where('email', $request->email)
+        $singleOptin = SingleOptin::query()->where('email', $request->email)
             ->whereHas('brand', function ($q) use ($service) {
-                $q->whereId($service->brand->id);
+                $q->where('id', $service->brand->id);
             })->firstOrNew();
 
         if ($request->opt_in) {
diff --git a/app/Http/Controllers/CustomerController.php b/app/Http/Controllers/CustomerController.php
index 2f1a026..05b4482 100644
--- a/app/Http/Controllers/CustomerController.php
+++ b/app/Http/Controllers/CustomerController.php
@@ -9,6 +9,7 @@ use App\Models\Customer;
 use App\Models\CustomerInfo;
 use App\Models\CustomerLogin;
 use App\Models\SingleOptin;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Query\JoinClause;
 use Illuminate\Http\Request;
 use Illuminate\Support\Carbon;
@@ -271,15 +272,16 @@ class CustomerController extends Controller
                 }
                 // ! Continue
             case CustomerExportType::singleOptin():
-                SingleOptin::where('brand_id', $request->brand)->get()
-                    ->map(function (SingleOptin $singleOptin) use ($w) {
-                        $w->insertOne([
-                            'lastname' => '',
-                            'firstname' => '',
-                            'email' => $singleOptin->email,
-                            'hashcode' => ''
-                        ]);
-                    });
+                SingleOptin::query()->whereHas('brand', function (Builder $q) use ($request) {
+                    $q->where('id', $request->brand);
+                })->get()->map(function (SingleOptin $singleOptin) use ($w) {
+                    $w->insertOne([
+                        'lastname' => '',
+                        'firstname' => '',
+                        'email' => $singleOptin->email,
+                        'hashcode' => $singleOptin->hashcode
+                    ]);
+                });
                 break;
             default:
                 throw new \Exception(sprintf('Unhandled CustomerExportType %s', $exportType->label));
diff --git a/app/Http/Controllers/SingleOptinController.php b/app/Http/Controllers/SingleOptinController.php
index dab4b66..4bbca5a 100644
--- a/app/Http/Controllers/SingleOptinController.php
+++ b/app/Http/Controllers/SingleOptinController.php
@@ -3,6 +3,7 @@
 namespace App\Http\Controllers;
 
 use App\Models\SingleOptin;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Http\Request;
 use Illuminate\Support\Str;
 
@@ -23,7 +24,9 @@ class SingleOptinController extends Controller
         $query = SingleOptin::query();
 
         if ($request->brand) {
-            $query = $query->where('brand_id', '=', request()->brand);
+            $query = $query->whereHas('brand', function (Builder $q) {
+                $q->where('id', request()->brand);
+            });
         }
         if ($request->search) {
             $this->searchQuery(
diff --git a/app/Jobs/StatJob.php b/app/Jobs/StatJob.php
index b4961e1..8ea412a 100644
--- a/app/Jobs/StatJob.php
+++ b/app/Jobs/StatJob.php
@@ -9,6 +9,7 @@ use App\Models\CustomerLogin;
 use App\Models\SingleOptin;
 use Illuminate\Bus\Queueable;
 use Illuminate\Contracts\Queue\ShouldQueue;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Foundation\Bus\Dispatchable;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Queue\Middleware\WithoutOverlapping;
@@ -57,17 +58,29 @@ class StatJob implements ShouldQueue
     public function handle()
     {
         $stats = new BrandStat([
-            'active' => CustomerLogin::whereBrandId($this->brand->id)
-                ->whereDate('last_connection', '<', Carbon::now()->subMonths(6))->count(),
-            'inactive' => CustomerLogin::whereBrandId($this->brand->id)
+            'active' => CustomerLogin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })->whereDate('last_connection', '<', Carbon::now()->subMonths(6))->count(),
+            'inactive' => CustomerLogin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })
                 ->whereDate('last_connection', '>', Carbon::now()->subMonths(6))->count(),
-            'new_accounts' => CustomerLogin::whereBrandId($this->brand->id)
+            'new_accounts' => CustomerLogin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })
                 ->whereDate('created_at', '<', Carbon::now()->subMonths(6))->count(),
-            'old_accounts' => CustomerLogin::whereBrandId($this->brand->id)
+            'old_accounts' => CustomerLogin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })
                 ->whereDate('created_at', '>', Carbon::now()->subMonths(6))->count(),
-            'total_accounts' => CustomerLogin::whereBrandId($this->brand->id)->count(),
-            'total_opt_in' => CustomerInfo::whereBrandId($this->brand->id)
-                ->whereOptIn(true)->count() + SingleOptin::whereBrandId($this->brand->id)->count()
+            'total_accounts' => CustomerLogin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })->count(),
+            'total_opt_in' => CustomerInfo::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })->whereOptIn(true)->count() + SingleOptin::query()->whereHas('brand', function (Builder $q) {
+                $q->where('id', $this->brand->id);
+            })->count()
         ]);
         $stats->brand()->associate($this->brand);
         $stats->saveOrFail();
diff --git a/app/Lib/MigrateOldData.php b/app/Lib/MigrateOldData.php
index 462edf6..5ce9ffe 100644
--- a/app/Lib/MigrateOldData.php
+++ b/app/Lib/MigrateOldData.php
@@ -10,6 +10,7 @@ use App\Models\CustomerLogin;
 use App\Models\SingleOptin;
 use Carbon\Exceptions\InvalidFormatException;
 use Database\migrations\LeGaulois2016Migration;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\File;
 use Illuminate\Support\Facades\Hash;
@@ -85,8 +86,10 @@ class MigrateOldData extends LeGaulois2016Migration
 
                             // * Just save Single optin.
                             if (empty($first_name) && empty($last_name)) {
-                                $sglOptin           = SingleOptin::where('email', strtolower($email))
-                                    ->where('brand_id', $this->brand->id)->firstOrNew();
+                                $sglOptin           = SingleOptin::query()->where('email', strtolower($email))
+                                    ->whereHas('brand', function (Builder $q) {
+                                        $q->where('id', $this->brand->id);
+                                    })->firstOrNew();
                                 $sglOptin->email    = strtolower($email);
                                 $sglOptin->brand_id = $this->brand->id;
                                 $sglOptin->save();
diff --git a/app/Models/SingleOptin.php b/app/Models/SingleOptin.php
index 526ad5e..8cf0a78 100644
--- a/app/Models/SingleOptin.php
+++ b/app/Models/SingleOptin.php
@@ -4,11 +4,33 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Str;
 
 class SingleOptin extends Model
 {
     use HasFactory;
 
+    /**
+     * The primary key for the model.
+     *
+     * @var string
+     */
+    protected $primaryKey = 'hashcode';
+
+    /**
+     * The "type" of the primary key ID.
+     *
+     * @var string
+     */
+    protected $keyType = 'uuid';
+
+    /**
+     * Indicates if the IDs are auto-incrementing.
+     *
+     * @var boolean
+     */
+    public $incrementing = false;
+
     /**
      * The attributes that are mass assignable.
      *
@@ -18,6 +40,18 @@ class SingleOptin extends Model
         'email'
     ];
 
+    /**
+     * Perform any actions required after the model boots.
+     *
+     * @return void
+     */
+    protected static function booted()
+    {
+        static::creating(function (self $model) {
+            $model->hashcode = Str::uuid();
+        });
+    }
+
     // * RELATIONS
 
     /**
diff --git a/database/migrations/2023_06_23_171318_add_change_single_optin_to_use_hashcode.php b/database/migrations/2023_06_23_171318_add_change_single_optin_to_use_hashcode.php
new file mode 100644
index 0000000..9c174fc
--- /dev/null
+++ b/database/migrations/2023_06_23_171318_add_change_single_optin_to_use_hashcode.php
@@ -0,0 +1,49 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Support\Str;
+
+class AddChangeSingleOptinToUseHashcode extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('single_optins', function (Blueprint $table) {
+            $table->uuid('hashcode')->comment('Single optin hashcode')->after('id');
+        });
+        DB::transaction(function () {
+            DB::table('single_optins')->get()->each(function (object $single_optin) {
+                DB::table('single_optins')->where('id', $single_optin->id)->update([
+                    'hashcode' => Str::uuid()
+                ]);
+            });
+        });
+        Schema::table('single_optins', function (Blueprint $table) {
+            $table->uuid('hashcode')->comment('Single optin hashcode')->after('id')
+                ->unique()->change();
+            $table->dropColumn('id');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('single_optins', function (Blueprint $table) {
+            $table->id()->after('hashcode');
+        });
+        Schema::table('single_optins', function (Blueprint $table) {
+            $table->dropColumn('hashcode');
+        });
+    }
+}
diff --git a/tests/CRM/ApiV2/CustomerTest.php b/tests/CRM/ApiV2/CustomerTest.php
index 1c1c6fa..ba84bb4 100644
--- a/tests/CRM/ApiV2/CustomerTest.php
+++ b/tests/CRM/ApiV2/CustomerTest.php
@@ -683,7 +683,7 @@ class CustomerTest extends ApiBase
 
         // * Delete Single optin if exists.
         /** @var \App\Models\SingleOptin|null $singleOptin */
-        $singleOptin = SingleOptin::where('email', $data['email'])
+        $singleOptin = SingleOptin::query()->where('email', $data['email'])
         ->whereHas('brand', function ($q) use ($brand) {
             $q->where('brands.id', '=', $brand->id);
         })->first();
diff --git a/tests/CRM/ApiV2/SingleOptinTest.php b/tests/CRM/ApiV2/SingleOptinTest.php
index f1ec95c..36d7c55 100644
--- a/tests/CRM/ApiV2/SingleOptinTest.php
+++ b/tests/CRM/ApiV2/SingleOptinTest.php
@@ -32,7 +32,7 @@ class SingleOptinTest extends ApiBase
         $json     = $response->decodeResponseJson();
         $this->assertApiResponseStatusIs($json, ApiStatus::OK());
         $this->assertTrue(
-            SingleOptin::where('email', 'singleoptin@hotmail.fr')->exists(),
+            SingleOptin::query()->where('email', 'singleoptin@hotmail.fr')->exists(),
             'Single optin should have been set for email "singleoptin@hotmail.fr"'
         );
     }
@@ -54,7 +54,7 @@ class SingleOptinTest extends ApiBase
         $json     = $response->decodeResponseJson();
         $this->assertApiResponseStatusIs($json, ApiStatus::OK());
         $this->assertFalse(
-            SingleOptin::where('email', 'singleoptin@hotmail.fr')->exists(),
+            SingleOptin::query()->where('email', 'singleoptin@hotmail.fr')->exists(),
             'Single optin should have been removed for email "singleoptin@hotmail.fr"'
         );
     }
@@ -71,7 +71,7 @@ class SingleOptinTest extends ApiBase
         $this->storeCustomer($service);
 
         // * Make sure a single optin exists.
-        $singleOptin = SingleOptin::whereEmail('singleoptin@hotmail.fr')->firstOrNew();
+        $singleOptin = SingleOptin::query()->where('email', 'singleoptin@hotmail.fr')->firstOrNew();
         $singleOptin->brand()->associate($service->brand);
         $singleOptin->email = 'singleoptin@hotmail.fr';
         $singleOptin->saveOrFail();
diff --git a/tests/Client/CrmClientV2CustomerTest.php b/tests/Client/CrmClientV2CustomerTest.php
index 1b19a55..e800bda 100644
--- a/tests/Client/CrmClientV2CustomerTest.php
+++ b/tests/Client/CrmClientV2CustomerTest.php
@@ -507,7 +507,7 @@ class CrmClientV2CustomerTest extends CrmClientTester
 
         // * Delete Single optin if exists.
         /** @var \App\Models\SingleOptin|null $singleOptin */
-        $singleOptin = SingleOptin::where('email', $data['email'])
+        $singleOptin = SingleOptin::query()->where('email', $data['email'])
         ->whereHas('brand', function ($q) use ($brand) {
             $q->where('brands.id', '=', $brand->id);
         })->first();
diff --git a/tests/Client/CrmClientV2SingleOptinTest.php b/tests/Client/CrmClientV2SingleOptinTest.php
index 7b33f37..0732781 100644
--- a/tests/Client/CrmClientV2SingleOptinTest.php
+++ b/tests/Client/CrmClientV2SingleOptinTest.php
@@ -24,14 +24,14 @@ class CrmClientV2SingleOptinTest extends CrmClientTester
     {
         // Set single optin and check.
         $this->assertTrue(SingleOptin::setStatus('singleoptinrandom@gmail.com', true));
-        $this->assertTrue(ModelsSingleOptin::where('email', 'singleoptinrandom@gmail.com')->exists());
+        $this->assertTrue(ModelsSingleOptin::query()->where('email', 'singleoptinrandom@gmail.com')->exists());
 
         // Set single optin again should not fail.
         $this->assertTrue(CrmApiV2::setStatus('singleoptinrandom@gmail.com', true));
 
         // Remove single optin test and check.
         $this->assertTrue(SingleOptin::setStatus('singleoptinrandom@gmail.com', false));
-        $this->assertTrue(!ModelsSingleOptin::where('email', 'singleoptinrandom@gmail.com')->exists());
+        $this->assertTrue(!ModelsSingleOptin::query()->where('email', 'singleoptinrandom@gmail.com')->exists());
     }
 
     /**