diff --git a/app/Domains/Administrator/Requests/StoreAdministratorRequest.php b/app/Domains/Administrator/Requests/StoreAdministratorRequest.php
index 529a181..9d49afd 100644
--- a/app/Domains/Administrator/Requests/StoreAdministratorRequest.php
+++ b/app/Domains/Administrator/Requests/StoreAdministratorRequest.php
@@ -31,7 +31,7 @@ class StoreAdministratorRequest extends FormRequest
                 'required',
                 'email',
                 'max:255',
-                Rule::unique('users', 'email')->whereNull('deleted_at'),
+                Rule::unique('users', 'active_email')->where('rol_codigo', RoleCode::AdminApp->value)->whereNull('deleted_at'),
             ],
         ];
     }
diff --git a/app/Domains/Administrator/Requests/UpdateAdministratorRequest.php b/app/Domains/Administrator/Requests/UpdateAdministratorRequest.php
index 6750789..9b95a46 100644
--- a/app/Domains/Administrator/Requests/UpdateAdministratorRequest.php
+++ b/app/Domains/Administrator/Requests/UpdateAdministratorRequest.php
@@ -32,7 +32,7 @@ class UpdateAdministratorRequest extends FormRequest
                 'required',
                 'email',
                 'max:255',
-                Rule::unique('users', 'email')
+                Rule::unique('users', 'active_email')->where('rol_codigo', RoleCode::AdminApp->value)
                     ->whereNull('deleted_at')
                     ->ignore($administratorId),
             ],
diff --git a/app/Domains/Auth/Requests/RegisterUserRequest.php b/app/Domains/Auth/Requests/RegisterUserRequest.php
index 5acfb09..155f7b8 100644
--- a/app/Domains/Auth/Requests/RegisterUserRequest.php
+++ b/app/Domains/Auth/Requests/RegisterUserRequest.php
@@ -2,6 +2,7 @@
 
 namespace App\Domains\Auth\Requests;
 
+use App\Domains\Authorization\Enums\RoleCode;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 use Illuminate\Validation\Rules\Password;
@@ -13,9 +14,14 @@ class RegisterUserRequest extends FormRequest
         return true;
     }
 
-    /**
-     * @return array<string, mixed>
-     */
+    protected function prepareForValidation(): void
+    {
+        if (is_string($this->input('email'))) {
+            $this->merge(['email' => mb_strtolower(trim($this->input('email')))]);
+        }
+    }
+
+    /** @return array<string, mixed> */
     public function rules(): array
     {
         return [
@@ -26,7 +32,7 @@ class RegisterUserRequest extends FormRequest
                 'string',
                 'email',
                 'max:255',
-                Rule::unique('users', 'email')->whereNull('deleted_at'),
+                Rule::unique('users', 'active_email')->where('rol_codigo', RoleCode::User->value)->whereNull('deleted_at'),
             ],
             'password' => ['required', 'string', 'confirmed', Password::min(8)->mixedCase()->symbols()],
             'dni' => ['nullable', 'string', 'max:255'],
diff --git a/app/Domains/Auth/Requests/UpdateProfileRequest.php b/app/Domains/Auth/Requests/UpdateProfileRequest.php
index a4984d7..f0a88cb 100644
--- a/app/Domains/Auth/Requests/UpdateProfileRequest.php
+++ b/app/Domains/Auth/Requests/UpdateProfileRequest.php
@@ -13,6 +13,13 @@ class UpdateProfileRequest extends FormRequest
         return true;
     }
 
+    protected function prepareForValidation(): void
+    {
+        if (is_string($this->input('email'))) {
+            $this->merge(['email' => mb_strtolower(trim($this->input('email')))]);
+        }
+    }
+
     public function rules(): array
     {
         return [
@@ -20,7 +27,7 @@ class UpdateProfileRequest extends FormRequest
             'email' => [
                 'required',
                 'email',
-                Rule::unique('users', 'email')
+                Rule::unique('users', 'active_email')->where('rol_codigo', $this->user()->rol_codigo)
                     ->whereNull('deleted_at')
                     ->ignore($this->user()->id),
             ],
diff --git a/app/Domains/Staff/Requests/StoreStaffRequest.php b/app/Domains/Staff/Requests/StoreStaffRequest.php
index b592e4a..4237318 100644
--- a/app/Domains/Staff/Requests/StoreStaffRequest.php
+++ b/app/Domains/Staff/Requests/StoreStaffRequest.php
@@ -2,6 +2,7 @@
 
 namespace App\Domains\Staff\Requests;
 
+use App\Domains\Authorization\Enums\RoleCode;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 
@@ -12,6 +13,13 @@ class StoreStaffRequest extends FormRequest
         return true;
     }
 
+    protected function prepareForValidation(): void
+    {
+        if (is_string($this->input('email'))) {
+            $this->merge(['email' => mb_strtolower(trim($this->input('email')))]);
+        }
+    }
+
     /** @return array<string, mixed> */
     public function rules(): array
     {
@@ -27,7 +35,7 @@ class StoreStaffRequest extends FormRequest
                 'required',
                 'email',
                 'max:255',
-                Rule::unique('users', 'email')->whereNull('deleted_at'),
+                Rule::unique('users', 'active_email')->where('rol_codigo', RoleCode::Scanner->value)->whereNull('deleted_at'),
             ],
             'category_ids' => $categoryRules,
             'category_ids.*' => ['integer', 'distinct', Rule::exists('categorias', 'id')],
diff --git a/app/Domains/Staff/Requests/UpdateStaffRequest.php b/app/Domains/Staff/Requests/UpdateStaffRequest.php
index 19e1a94..fcf6e3f 100644
--- a/app/Domains/Staff/Requests/UpdateStaffRequest.php
+++ b/app/Domains/Staff/Requests/UpdateStaffRequest.php
@@ -2,6 +2,7 @@
 
 namespace App\Domains\Staff\Requests;
 
+use App\Domains\Authorization\Enums\RoleCode;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 
@@ -12,6 +13,13 @@ class UpdateStaffRequest extends FormRequest
         return true;
     }
 
+    protected function prepareForValidation(): void
+    {
+        if (is_string($this->input('email'))) {
+            $this->merge(['email' => mb_strtolower(trim($this->input('email')))]);
+        }
+    }
+
     /** @return array<string, mixed> */
     public function rules(): array
     {
@@ -28,7 +36,7 @@ class UpdateStaffRequest extends FormRequest
                 'required',
                 'email',
                 'max:255',
-                Rule::unique('users', 'email')
+                Rule::unique('users', 'active_email')->where('rol_codigo', RoleCode::Scanner->value)
                     ->whereNull('deleted_at')
                     ->ignore($staffId),
             ],
diff --git a/database/migrations/2026_09_04_000000_scope_active_email_unique_per_role.php b/database/migrations/2026_09_04_000000_scope_active_email_unique_per_role.php
new file mode 100644
index 0000000..557a0f7
--- /dev/null
+++ b/database/migrations/2026_09_04_000000_scope_active_email_unique_per_role.php
@@ -0,0 +1,24 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table): void {
+            $table->unique(['active_email', 'rol_codigo']);
+            $table->dropUnique(['active_email']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table): void {
+            $table->unique('active_email');
+            $table->dropUnique(['active_email', 'rol_codigo']);
+        });
+    }
+};
diff --git a/tests/Feature/Administrator/AdministratorControllerTest.php b/tests/Feature/Administrator/AdministratorControllerTest.php
index ddd160e..407592a 100644
--- a/tests/Feature/Administrator/AdministratorControllerTest.php
+++ b/tests/Feature/Administrator/AdministratorControllerTest.php
@@ -60,6 +60,17 @@ class AdministratorControllerTest extends TestCase
         return ['nombre_apellido' => 'Ada Lovelace', 'dni' => '12345678', 'email' => 'ada@example.test'];
     }
 
+    public function test_email_can_be_shared_with_customers_and_scanners(): void
+    {
+        Sanctum::actingAs($this->admin);
+        foreach (['user', 'scanner'] as $role) {
+            User::factory()->create(['email' => 'ada@example.test', 'rol_codigo' => $role]);
+        }
+        $response = $this->postJson(self::URL, $this->payload())->assertCreated();
+        $this->putJson(self::URL.'/'.$response->json('data.id'), $this->payload())->assertOk();
+        $this->postJson(self::URL, $this->payload())->assertUnprocessable()->assertJsonValidationErrors('email');
+    }
+
     public function test_crud_and_password_setup_and_token_revocation(): void
     {
         Sanctum::actingAs($this->admin);
diff --git a/tests/Feature/Auth/EmailUniquenessPerRoleTest.php b/tests/Feature/Auth/EmailUniquenessPerRoleTest.php
new file mode 100644
index 0000000..a4e9d8d
--- /dev/null
+++ b/tests/Feature/Auth/EmailUniquenessPerRoleTest.php
@@ -0,0 +1,133 @@
+<?php
+
+namespace Tests\Feature\Auth;
+
+use App\Domains\Attachable\Enums\AttachmentType;
+use App\Domains\Attachable\Models\Attachment;
+use App\Domains\Auth\Models\ResetPasswordAttempt;
+use App\Domains\Auth\Models\User;
+use App\Domains\Authorization\Enums\RoleCode;
+use App\Domains\Notification\Events\PasswordResetRequested;
+use App\Domains\Tenant\Models\Tenant;
+use Database\Seeders\AuthorizationSeeder;
+use Illuminate\Database\UniqueConstraintViolationException;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Routing\Middleware\ThrottleRequests;
+use Illuminate\Support\Facades\Event;
+use Illuminate\Support\Facades\Hash;
+use Tests\TestCase;
+
+class EmailUniquenessPerRoleTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->withoutMiddleware(ThrottleRequests::class);
+        $this->seed(AuthorizationSeeder::class);
+        Event::fake([PasswordResetRequested::class]);
+    }
+
+    public function test_database_allows_different_roles_and_reuse_after_soft_delete(): void
+    {
+        foreach (RoleCode::cases() as $role) {
+            User::factory()->create(['email' => 'Shared@example.com', 'rol_codigo' => $role->value]);
+        }
+        $user = User::where('rol_codigo', 'user')->sole();
+        $user->delete();
+        $replacement = User::factory()->create(['email' => 'shared@example.com']);
+        $this->assertNotSame($user->id, $replacement->id);
+        $this->assertSame(4, User::where('active_email', 'shared@example.com')->count());
+    }
+
+    public function test_database_rejects_same_role_case_insensitively_across_tenants(): void
+    {
+        foreach (['one', 'two'] as $code) {
+            $this->createTenant($code);
+        }
+        User::factory()->create(['email' => 'Shared@example.com', 'tenant_codigo' => 'one']);
+        $this->expectException(UniqueConstraintViolationException::class);
+        User::factory()->create(['email' => 'shared@example.com', 'tenant_codigo' => 'two']);
+    }
+
+    public function test_role_change_cannot_create_a_duplicate_active_identity(): void
+    {
+        User::factory()->create(['email' => 'shared@example.com']);
+        $admin = User::factory()->create(['email' => 'shared@example.com', 'rol_codigo' => 'adminapp']);
+        $this->expectException(UniqueConstraintViolationException::class);
+        $admin->update(['rol_codigo' => 'user']);
+    }
+
+    public function test_registration_accepts_another_role_but_rejects_same_role(): void
+    {
+        User::factory()->create(['email' => 'SHARED@example.com', 'rol_codigo' => 'adminapp']);
+        $payload = ['nombre_apellido' => 'Shared', 'email' => ' Shared@Example.com ',
+            'password' => 'Secret!123', 'password_confirmation' => 'Secret!123'];
+        $this->postJson('/api/register', $payload)->assertCreated()->assertJsonPath('data.email', 'shared@example.com');
+        $this->postJson('/api/register', $payload)->assertUnprocessable()->assertJsonValidationErrors('email');
+    }
+
+    public function test_login_and_password_reset_select_the_role_from_each_application(): void
+    {
+        $tenant = $this->createTenant('acme');
+        $users = [];
+        // Create staff first so an email-only lookup would select the wrong account.
+        foreach (['adminapp', 'scanner', 'user'] as $role) {
+            $users[$role] = User::factory()->create([
+                'email' => 'Shared@example.com', 'rol_codigo' => $role,
+                'tenant_codigo' => $tenant->codigo, 'password' => 'Old!'.$role,
+            ]);
+        }
+        foreach (['user' => '/api', 'adminapp' => '/api/v1/adminapp', 'scanner' => '/api/v1/scanner'] as $role => $base) {
+            $this->postJson($base.'/login', [
+                'email' => 'SHARED@example.com', 'password' => 'Old!'.$role, 'tenant_codigo' => 'acme',
+            ])->assertOk()->assertJsonPath('user.id', $users[$role]->id);
+            $this->postJson($base.'/password/reset-attempts', [
+                'email' => 'shared@example.com', 'tenant_codigo' => 'acme',
+            ])->assertAccepted();
+        }
+        // Identical codes across roles must still only change the intended account.
+        ResetPasswordAttempt::query()->update(['codigo' => '1234']);
+        foreach (['user' => '/api', 'adminapp' => '/api/v1/adminapp', 'scanner' => '/api/v1/scanner'] as $role => $base) {
+            $this->postJson($base.'/password/reset-attempts/validate', [
+                'email' => 'shared@example.com', 'codigo' => '1234',
+            ])->assertOk();
+            $this->postJson($base.'/password/reset', [
+                'email' => 'shared@example.com', 'codigo' => '1234',
+                'password' => 'New!'.$role, 'password_confirmation' => 'New!'.$role,
+            ])->assertOk();
+            $this->assertTrue(Hash::check('New!'.$role, $users[$role]->fresh()->password));
+        }
+    }
+
+    private function createTenant(string $code): Tenant
+    {
+        $headerLogo = $this->createAttachment("{$code}-header");
+        $footerLogo = $this->createAttachment("{$code}-footer");
+
+        return Tenant::query()->create([
+            'codigo' => $code,
+            'nombre' => ucfirst($code),
+            'dominio' => "{$code}.local",
+            'primary_color' => '#000000',
+            'secondary_color' => '#000000',
+            'danger_color' => '#000000',
+            'success_color' => '#000000',
+            'header_bg_color' => '#000000',
+            'footer_bg_color' => '#000000',
+            'header_logo_id' => $headerLogo->id,
+            'footer_logo_id' => $footerLogo->id,
+        ]);
+    }
+
+    private function createAttachment(string $name): Attachment
+    {
+        return Attachment::query()->create([
+            'path' => "test/{$name}.png",
+            'filename' => "{$name}.png",
+            'type' => AttachmentType::Image,
+            'mime_type' => 'image/png',
+        ]);
+    }
+}
diff --git a/tests/Feature/Staff/StaffControllerTest.php b/tests/Feature/Staff/StaffControllerTest.php
index 194cd35..9f4ebd0 100644
--- a/tests/Feature/Staff/StaffControllerTest.php
+++ b/tests/Feature/Staff/StaffControllerTest.php
@@ -56,6 +56,17 @@ class StaffControllerTest extends TestCase
         ]);
     }
 
+    public function test_staff_email_can_be_shared_with_adminapp_and_customers(): void
+    {
+        Sanctum::actingAs($this->admin);
+        User::factory()->create(['email' => $this->admin->email]);
+        $payload = ['nombre_apellido' => 'Shared', 'dni' => '12345678',
+            'email' => strtoupper($this->admin->email), 'category_ids' => [$this->createCategory('Tickets')->id]];
+        $response = $this->postJson('/api/v1/adminapp/tenant/staff', $payload)->assertSuccessful();
+        $this->putJson('/api/v1/adminapp/tenant/staff/'.$response->json('data.id'), $payload)->assertOk();
+        $this->postJson('/api/v1/adminapp/tenant/staff', $payload)->assertUnprocessable()->assertJsonValidationErrors('email');
+    }
+
     public function test_adminapp_can_create_update_list_and_delete_staff_with_categories(): void
     {
         Sanctum::actingAs($this->admin);