diff --git a/Webshop.Api/Controllers/Admin/AdminShippingMethodsController.cs b/Webshop.Api/Controllers/Admin/AdminShippingMethodsController.cs
index 52c175c..f2a367c 100644
--- a/Webshop.Api/Controllers/Admin/AdminShippingMethodsController.cs
+++ b/Webshop.Api/Controllers/Admin/AdminShippingMethodsController.cs
@@ -1,9 +1,11 @@
 // src/Webshop.Api/Controllers/Admin/AdminShippingMethodsController.cs
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Webshop.Application;
 using Webshop.Application.DTOs.Shipping;
 using Webshop.Application.Services.Admin;
 
@@ -21,43 +23,90 @@ namespace Webshop.Api.Controllers.Admin
             _shippingMethodService = shippingMethodService;
         }
 
-        [HttpPost]
-        public async Task<ActionResult<ShippingMethodDto>> CreateShippingMethod([FromBody] ShippingMethodDto shippingMethodDto)
+        [HttpGet]
+        [ProducesResponseType(typeof(IEnumerable<ShippingMethodDto>), StatusCodes.Status200OK)]
+        public async Task<IActionResult> GetAllShippingMethods()
         {
-            var createdMethod = await _shippingMethodService.CreateAsync(shippingMethodDto);
-            return CreatedAtAction(nameof(GetShippingMethodById), new { id = createdMethod.Id }, createdMethod);
+            var result = await _shippingMethodService.GetAllAsync();
+            return Ok(result.Value);
         }
 
         [HttpGet("{id}")]
-        public async Task<ActionResult<ShippingMethodDto>> GetShippingMethodById(Guid id)
+        [ProducesResponseType(typeof(ShippingMethodDto), StatusCodes.Status200OK)]
+        [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
+        public async Task<IActionResult> GetShippingMethodById(Guid id)
         {
-            var method = await _shippingMethodService.GetByIdAsync(id);
-            if (method == null) return NotFound();
-            return Ok(method);
+            var result = await _shippingMethodService.GetByIdAsync(id);
+
+            return result.Type switch
+            {
+                ServiceResultType.Success => Ok(result.Value),
+                ServiceResultType.NotFound => NotFound(new { Message = result.ErrorMessage }),
+                _ => StatusCode(StatusCodes.Status500InternalServerError, new { Message = result.ErrorMessage ?? "Ein unerwarteter Fehler ist aufgetreten." })
+            };
         }
 
-        [HttpGet]
-        public async Task<ActionResult<IEnumerable<ShippingMethodDto>>> GetAllShippingMethods()
+        [HttpPost]
+        [ProducesResponseType(typeof(ShippingMethodDto), StatusCodes.Status201Created)]
+        [ProducesResponseType(typeof(ValidationProblemDetails), StatusCodes.Status400BadRequest)]
+        [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status409Conflict)]
+        public async Task<IActionResult> CreateShippingMethod([FromBody] ShippingMethodDto shippingMethodDto)
         {
-            var methods = await _shippingMethodService.GetAllAsync();
-            return Ok(methods);
+            if (!ModelState.IsValid)
+            {
+                return BadRequest(ModelState);
+            }
+
+            var result = await _shippingMethodService.CreateAsync(shippingMethodDto);
+
+            return result.Type switch
+            {
+                ServiceResultType.Success => CreatedAtAction(nameof(GetShippingMethodById), new { id = result.Value!.Id }, result.Value),
+                ServiceResultType.Conflict => Conflict(new { Message = result.ErrorMessage }),
+                _ => StatusCode(StatusCodes.Status500InternalServerError, new { Message = result.ErrorMessage ?? "Ein unerwarteter Fehler ist aufgetreten." })
+            };
         }
 
         [HttpPut("{id}")]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(typeof(ValidationProblemDetails), StatusCodes.Status400BadRequest)]
+        [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
+        [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status409Conflict)]
         public async Task<IActionResult> UpdateShippingMethod(Guid id, [FromBody] ShippingMethodDto shippingMethodDto)
         {
-            if (id != shippingMethodDto.Id) return BadRequest();
-            var success = await _shippingMethodService.UpdateAsync(shippingMethodDto);
-            if (!success) return NotFound();
-            return NoContent();
+            if (id != shippingMethodDto.Id)
+            {
+                return BadRequest(new { Message = "ID in der URL und im Body stimmen nicht überein." });
+            }
+            if (!ModelState.IsValid)
+            {
+                return BadRequest(ModelState);
+            }
+
+            var result = await _shippingMethodService.UpdateAsync(shippingMethodDto);
+
+            return result.Type switch
+            {
+                ServiceResultType.Success => NoContent(),
+                ServiceResultType.NotFound => NotFound(new { Message = result.ErrorMessage }),
+                ServiceResultType.Conflict => Conflict(new { Message = result.ErrorMessage }),
+                _ => StatusCode(StatusCodes.Status500InternalServerError, new { Message = result.ErrorMessage ?? "Ein unerwarteter Fehler ist aufgetreten." })
+            };
         }
 
         [HttpDelete("{id}")]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
         public async Task<IActionResult> DeleteShippingMethod(Guid id)
         {
-            var success = await _shippingMethodService.DeleteAsync(id);
-            if (!success) return NotFound();
-            return NoContent();
+            var result = await _shippingMethodService.DeleteAsync(id);
+
+            return result.Type switch
+            {
+                ServiceResultType.Success => NoContent(),
+                ServiceResultType.NotFound => NotFound(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/AdminShippingMethodService.cs b/Webshop.Application/Services/Admin/AdminShippingMethodService.cs
index 4d9ea6f..0cf8c7d 100644
--- a/Webshop.Application/Services/Admin/AdminShippingMethodService.cs
+++ b/Webshop.Application/Services/Admin/AdminShippingMethodService.cs
@@ -3,6 +3,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Webshop.Application;
 using Webshop.Application.DTOs.Shipping;
 using Webshop.Domain.Entities;
 using Webshop.Domain.Interfaces;
@@ -18,38 +19,31 @@ namespace Webshop.Application.Services.Admin
             _shippingMethodRepository = shippingMethodRepository;
         }
 
-        public async Task<IEnumerable<ShippingMethodDto>> GetAllAsync()
+        public async Task<ServiceResult<IEnumerable<ShippingMethodDto>>> GetAllAsync()
         {
             var methods = await _shippingMethodRepository.GetAllAsync();
-            return methods.Select(sm => new ShippingMethodDto
-            {
-                Id = sm.Id,
-                Name = sm.Name,
-                Description = sm.Description,
-                Cost = sm.BaseCost,
-                IsActive = sm.IsActive,
-                MinDeliveryDays = 0, // Annahme, diese Felder existieren in Ihrer Entität
-                MaxDeliveryDays = 0  // Annahme, diese Felder existieren in Ihrer Entität
-            }).ToList();
+            var dtos = methods.Select(MapToDto).ToList();
+            return ServiceResult.Ok<IEnumerable<ShippingMethodDto>>(dtos);
         }
 
-        public async Task<ShippingMethodDto?> GetByIdAsync(Guid id)
+        public async Task<ServiceResult<ShippingMethodDto>> GetByIdAsync(Guid id)
         {
             var sm = await _shippingMethodRepository.GetByIdAsync(id);
-            if (sm == null) return null;
-
-            return new ShippingMethodDto
+            if (sm == null)
             {
-                Id = sm.Id,
-                Name = sm.Name,
-                Description = sm.Description,
-                Cost = sm.BaseCost,
-                IsActive = sm.IsActive
-            };
+                return ServiceResult.Fail<ShippingMethodDto>(ServiceResultType.NotFound, $"Versandmethode mit ID '{id}' nicht gefunden.");
+            }
+            return ServiceResult.Ok(MapToDto(sm));
         }
 
-        public async Task<ShippingMethodDto> CreateAsync(ShippingMethodDto shippingMethodDto)
+        public async Task<ServiceResult<ShippingMethodDto>> CreateAsync(ShippingMethodDto shippingMethodDto)
         {
+            var allMethods = await _shippingMethodRepository.GetAllAsync();
+            if (allMethods.Any(sm => sm.Name.Equals(shippingMethodDto.Name, StringComparison.OrdinalIgnoreCase)))
+            {
+                return ServiceResult.Fail<ShippingMethodDto>(ServiceResultType.Conflict, $"Eine Versandmethode mit dem Namen '{shippingMethodDto.Name}' existiert bereits.");
+            }
+
             var newMethod = new ShippingMethod
             {
                 Id = Guid.NewGuid(),
@@ -60,14 +54,24 @@ namespace Webshop.Application.Services.Admin
             };
 
             await _shippingMethodRepository.AddAsync(newMethod);
+
             shippingMethodDto.Id = newMethod.Id;
-            return shippingMethodDto;
+            return ServiceResult.Ok(shippingMethodDto);
         }
 
-        public async Task<bool> UpdateAsync(ShippingMethodDto shippingMethodDto)
+        public async Task<ServiceResult> UpdateAsync(ShippingMethodDto shippingMethodDto)
         {
             var existingMethod = await _shippingMethodRepository.GetByIdAsync(shippingMethodDto.Id);
-            if (existingMethod == null) return false;
+            if (existingMethod == null)
+            {
+                return ServiceResult.Fail(ServiceResultType.NotFound, $"Versandmethode mit ID '{shippingMethodDto.Id}' nicht gefunden.");
+            }
+
+            var allMethods = await _shippingMethodRepository.GetAllAsync();
+            if (allMethods.Any(sm => sm.Name.Equals(shippingMethodDto.Name, StringComparison.OrdinalIgnoreCase) && sm.Id != shippingMethodDto.Id))
+            {
+                return ServiceResult.Fail(ServiceResultType.Conflict, $"Eine andere Versandmethode mit dem Namen '{shippingMethodDto.Name}' existiert bereits.");
+            }
 
             existingMethod.Name = shippingMethodDto.Name;
             existingMethod.Description = shippingMethodDto.Description;
@@ -75,16 +79,31 @@ namespace Webshop.Application.Services.Admin
             existingMethod.IsActive = shippingMethodDto.IsActive;
 
             await _shippingMethodRepository.UpdateAsync(existingMethod);
-            return true;
+            return ServiceResult.Ok();
         }
 
-        public async Task<bool> DeleteAsync(Guid id)
+        public async Task<ServiceResult> DeleteAsync(Guid id)
         {
             var method = await _shippingMethodRepository.GetByIdAsync(id);
-            if (method == null) return false;
+            if (method == null)
+            {
+                return ServiceResult.Fail(ServiceResultType.NotFound, $"Versandmethode mit ID '{id}' nicht gefunden.");
+            }
 
             await _shippingMethodRepository.DeleteAsync(id);
-            return true;
+            return ServiceResult.Ok();
+        }
+
+        private ShippingMethodDto MapToDto(ShippingMethod sm)
+        {
+            return new ShippingMethodDto
+            {
+                Id = sm.Id,
+                Name = sm.Name,
+                Description = sm.Description,
+                Cost = sm.BaseCost,
+                IsActive = sm.IsActive
+            };
         }
     }
 }
\ No newline at end of file
diff --git a/Webshop.Application/Services/Admin/Interfaces/IAdminShippingMethodService.cs b/Webshop.Application/Services/Admin/Interfaces/IAdminShippingMethodService.cs
index 471e718..8a93c5d 100644
--- a/Webshop.Application/Services/Admin/Interfaces/IAdminShippingMethodService.cs
+++ b/Webshop.Application/Services/Admin/Interfaces/IAdminShippingMethodService.cs
@@ -2,16 +2,17 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using Webshop.Application.DTOs.Shipping; // Für ShippingMethodDto
+using Webshop.Application;
+using Webshop.Application.DTOs.Shipping;
 
 namespace Webshop.Application.Services.Admin
 {
     public interface IAdminShippingMethodService
     {
-        Task<IEnumerable<ShippingMethodDto>> GetAllAsync();
-        Task<ShippingMethodDto?> GetByIdAsync(Guid id);
-        Task<ShippingMethodDto> CreateAsync(ShippingMethodDto shippingMethodDto);
-        Task<bool> UpdateAsync(ShippingMethodDto shippingMethodDto);
-        Task<bool> DeleteAsync(Guid id);
+        Task<ServiceResult<IEnumerable<ShippingMethodDto>>> GetAllAsync();
+        Task<ServiceResult<ShippingMethodDto>> GetByIdAsync(Guid id);
+        Task<ServiceResult<ShippingMethodDto>> CreateAsync(ShippingMethodDto shippingMethodDto);
+        Task<ServiceResult> UpdateAsync(ShippingMethodDto shippingMethodDto);
+        Task<ServiceResult> DeleteAsync(Guid id);
     }
 }
\ No newline at end of file