diff --git a/Webshop.Api/Controllers/Admin/AdminSettingsController.cs b/Webshop.Api/Controllers/Admin/AdminSettingsController.cs
index 1e88cef..2dbd0da 100644
--- a/Webshop.Api/Controllers/Admin/AdminSettingsController.cs
+++ b/Webshop.Api/Controllers/Admin/AdminSettingsController.cs
@@ -1,8 +1,10 @@
 // src/Webshop.Api/Controllers/Admin/AdminSettingsController.cs
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Webshop.Application;
 using Webshop.Application.DTOs.Settings;
 using Webshop.Application.Services.Admin.Interfaces;
 
@@ -21,21 +23,31 @@ namespace Webshop.Api.Controllers.Admin
         }
 
         [HttpGet]
-        public async Task<ActionResult<Dictionary<string, List<SettingDto>>>> GetAllSettings()
+        [ProducesResponseType(typeof(Dictionary<string, List<SettingDto>>), StatusCodes.Status200OK)]
+        public async Task<IActionResult> GetAllSettings()
         {
-            var settings = await _adminSettingService.GetAllGroupedAsync();
-            return Ok(settings);
+            var result = await _adminSettingService.GetAllGroupedAsync();
+            return Ok(result.Value);
         }
 
         [HttpPut]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(typeof(ValidationProblemDetails), StatusCodes.Status400BadRequest)]
         public async Task<IActionResult> UpdateSettings([FromBody] List<SettingDto> settings)
         {
             if (!ModelState.IsValid)
             {
                 return BadRequest(ModelState);
             }
-            await _adminSettingService.UpdateSettingsAsync(settings);
-            return NoContent();
+
+            var result = await _adminSettingService.UpdateSettingsAsync(settings);
+
+            return result.Type switch
+            {
+                ServiceResultType.Success => NoContent(),
+                ServiceResultType.InvalidInput => BadRequest(new { Message = result.ErrorMessage }),
+                _ => StatusCode(StatusCodes.Status500InternalServerError, new { Message = result.ErrorMessage ?? "Ein unerwarteter Fehler ist aufgetreten." })
+            };
         }
     }
 }
\ No newline at end of file
diff --git a/Webshop.Application/Services/Admin/AdminSettingService.cs b/Webshop.Application/Services/Admin/AdminSettingService.cs
index f8f4c01..3d4202f 100644
--- a/Webshop.Application/Services/Admin/AdminSettingService.cs
+++ b/Webshop.Application/Services/Admin/AdminSettingService.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Webshop.Application;
 using Webshop.Application.DTOs.Settings;
 using Webshop.Application.Services.Admin.Interfaces;
 using Webshop.Domain.Interfaces;
@@ -17,11 +18,11 @@ namespace Webshop.Application.Services.Admin
             _settingRepository = settingRepository;
         }
 
-        public async Task<Dictionary<string, List<SettingDto>>> GetAllGroupedAsync()
+        public async Task<ServiceResult<Dictionary<string, List<SettingDto>>>> GetAllGroupedAsync()
         {
             var settings = await _settingRepository.GetAllAsync();
 
-            return settings
+            var groupedSettings = settings
                 .GroupBy(s => s.Group ?? "Uncategorized")
                 .ToDictionary(
                     g => g.Key,
@@ -34,20 +35,35 @@ namespace Webshop.Application.Services.Admin
                         Group = s.Group
                     }).ToList()
                 );
+
+            return ServiceResult.Ok(groupedSettings);
         }
 
-        public async Task UpdateSettingsAsync(List<SettingDto> settings)
+        public async Task<ServiceResult> UpdateSettingsAsync(List<SettingDto> settings)
         {
+            var existingSettings = await _settingRepository.GetAllAsync();
+            var existingKeys = existingSettings.Select(s => s.Key).ToHashSet();
+
+            var invalidKeys = settings.Where(s => !existingKeys.Contains(s.Key)).Select(s => s.Key).ToList();
+            if (invalidKeys.Any())
+            {
+                return ServiceResult.Fail(ServiceResultType.InvalidInput, $"Die folgenden Einstellungsschlüssel wurden nicht gefunden: {string.Join(", ", invalidKeys)}");
+            }
+
+            // Umwandlung in ein Dictionary für effizienten Zugriff
+            var settingsDict = existingSettings.ToDictionary(s => s.Key);
+
             foreach (var settingDto in settings)
             {
-                var setting = await _settingRepository.GetByKeyAsync(settingDto.Key);
-                if (setting != null)
+                if (settingsDict.TryGetValue(settingDto.Key, out var setting))
                 {
                     setting.Value = settingDto.Value;
-                    setting.IsActive = settingDto.IsActive; // Auch IsActive aktualisieren
+                    setting.IsActive = settingDto.IsActive;
                     await _settingRepository.UpdateAsync(setting);
                 }
             }
+
+            return ServiceResult.Ok();
         }
     }
 }
\ No newline at end of file
diff --git a/Webshop.Application/Services/Admin/Interfaces/IAdminSettingService.cs b/Webshop.Application/Services/Admin/Interfaces/IAdminSettingService.cs
index 05dc8ad..7c27d5b 100644
--- a/Webshop.Application/Services/Admin/Interfaces/IAdminSettingService.cs
+++ b/Webshop.Application/Services/Admin/Interfaces/IAdminSettingService.cs
@@ -1,13 +1,14 @@
 // src/Webshop.Application/Services/Admin/Interfaces/IAdminSettingService.cs
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Webshop.Application;
 using Webshop.Application.DTOs.Settings;
 
 namespace Webshop.Application.Services.Admin.Interfaces
 {
     public interface IAdminSettingService
     {
-        Task<Dictionary<string, List<SettingDto>>> GetAllGroupedAsync();
-        Task UpdateSettingsAsync(List<SettingDto> settings);
+        Task<ServiceResult<Dictionary<string, List<SettingDto>>>> GetAllGroupedAsync();
+        Task<ServiceResult> UpdateSettingsAsync(List<SettingDto> settings);
     }
 }
\ No newline at end of file