diff --git a/Webshop.Api/Controllers/Admin/AdminSuppliersController.cs b/Webshop.Api/Controllers/Admin/AdminSuppliersController.cs
index d588e26..c4225fb 100644
--- a/Webshop.Api/Controllers/Admin/AdminSuppliersController.cs
+++ b/Webshop.Api/Controllers/Admin/AdminSuppliersController.cs
@@ -1,22 +1,23 @@
 // src/Webshop.Api/Controllers/Admin/AdminSuppliersController.cs
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
-using Webshop.Application.DTOs; // SupplierDto
-using Webshop.Application.Services.Admin; // AdminSupplierService
-using System.Collections.Generic; // Für IEnumerable
-using System.Threading.Tasks; // Für Task
+using Webshop.Application.DTOs;
+using Webshop.Application.Services.Admin; // Wichtig für IAdminSupplierService
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 
 namespace Webshop.Api.Controllers.Admin
 {
     [ApiController]
-    [Route("api/v1/admin/[controller]")] // z.B. /api/v1/admin/suppliers
-    [Authorize(Roles = "Admin")] // Nur Admins
+    [Route("api/v1/admin/[controller]")]
+    [Authorize(Roles = "Admin")]
     public class AdminSuppliersController : ControllerBase
     {
-        // HIER MUSS NUR EINE EINZIGE DEKLARATION STEHEN
-        private readonly AdminSupplierService _adminSupplierService;
+        // Der Controller hängt vom Interface ab, nicht von der konkreten Klasse
+        private readonly IAdminSupplierService _adminSupplierService;
 
-        public AdminSuppliersController(AdminSupplierService adminSupplierService)
+        public AdminSuppliersController(IAdminSupplierService adminSupplierService)
         {
             _adminSupplierService = adminSupplierService;
         }
@@ -28,20 +29,43 @@ namespace Webshop.Api.Controllers.Admin
             return Ok(suppliers);
         }
 
-        [HttpPost]
-        public async Task<ActionResult<SupplierDto>> CreateSupplier([FromBody] SupplierDto supplierDto)
-        {
-            if (!ModelState.IsValid) return BadRequest(ModelState);
-            var createdSupplier = await _adminSupplierService.CreateSupplierAsync(supplierDto);
-            return CreatedAtAction(nameof(GetSupplierById), new { id = createdSupplier.Id }, createdSupplier);
-        }
-
-        [HttpGet("{id}")]
+        [HttpGet("{id:guid}")]
         public async Task<ActionResult<SupplierDto>> GetSupplierById(Guid id)
         {
             var supplier = await _adminSupplierService.GetSupplierByIdAsync(id);
             if (supplier == null) return NotFound();
             return Ok(supplier);
         }
+
+        [HttpPost]
+        public async Task<ActionResult<SupplierDto>> CreateSupplier([FromBody] SupplierDto supplierDto)
+        {
+            if (supplierDto == null) return BadRequest("Supplier data is required.");
+            if (!ModelState.IsValid) return BadRequest(ModelState);
+
+            var createdSupplier = await _adminSupplierService.CreateSupplierAsync(supplierDto);
+            return CreatedAtAction(nameof(GetSupplierById), new { id = createdSupplier.Id }, createdSupplier);
+        }
+
+        [HttpPut("{id:guid}")]
+        public async Task<IActionResult> UpdateSupplier(Guid id, [FromBody] SupplierDto supplierDto)
+        {
+            if (id != supplierDto.Id) return BadRequest("Mismatched ID in route and body.");
+            if (!ModelState.IsValid) return BadRequest(ModelState);
+
+            var success = await _adminSupplierService.UpdateSupplierAsync(id, supplierDto);
+            if (!success) return NotFound();
+
+            return NoContent(); // Standardantwort für erfolgreiches Update
+        }
+
+        [HttpDelete("{id:guid}")]
+        public async Task<IActionResult> DeleteSupplier(Guid id)
+        {
+            var success = await _adminSupplierService.DeleteSupplierAsync(id);
+            if (!success) return NotFound();
+
+            return NoContent(); // Standardantwort für erfolgreiches Löschen
+        }
     }
 }
\ No newline at end of file
diff --git a/Webshop.Api/Program.cs b/Webshop.Api/Program.cs
index 215c100..a6d5e34 100644
--- a/Webshop.Api/Program.cs
+++ b/Webshop.Api/Program.cs
@@ -65,19 +65,20 @@ builder.Services.AddAuthentication(options =>
 builder.Services.AddAuthorization(); // Aktiviert die Autorisierung
 
 // 4. Unsere eigenen Interfaces und Klassen registrieren (Dependency Injection)
+// Repositories
 builder.Services.AddScoped<IProductRepository, ProductRepository>();
-builder.Services.AddScoped<ISupplierRepository, SupplierRepository>(); // NEU
+builder.Services.AddScoped<ISupplierRepository, SupplierRepository>();
 
 // AUTH Services
 builder.Services.AddScoped<IAuthService, AuthService>();
 
 // PUBLIC Services
-builder.Services.AddScoped<ProductService>(); // Ihr ProductService ist hier registriert
+builder.Services.AddScoped<IProductService, ProductService>();
 
 // ADMIN Services
-builder.Services.AddScoped<AdminUserService>();
-builder.Services.AddScoped<AdminProductService>();
-builder.Services.AddScoped<AdminSupplierService>(); // NEU
+builder.Services.AddScoped<IAdminUserService, AdminUserService>();
+builder.Services.AddScoped<IAdminProductService, AdminProductService>();
+builder.Services.AddScoped<IAdminSupplierService, AdminSupplierService>();
 
 // CUSTOMER Services (später Implementierungen hinzufügen)
 // builder.Services.AddScoped<CustomerOrderService>();
diff --git a/Webshop.Application/Services/Admin/AdminSupplierService.cs b/Webshop.Application/Services/Admin/AdminSupplierService.cs
index 56f25c0..532cb85 100644
--- a/Webshop.Application/Services/Admin/AdminSupplierService.cs
+++ b/Webshop.Application/Services/Admin/AdminSupplierService.cs
@@ -1,27 +1,109 @@
-// Auto-generiert von CreateWebshopFiles.ps1
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
+// src/Webshop.Application/Services/Admin/AdminSupplierService.cs
 using Webshop.Application.DTOs;
 using Webshop.Domain.Entities;
-using Webshop.Domain.Interfaces;
-
+using Webshop.Domain.Interfaces; // Wichtig für ISupplierRepository
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
 
 namespace Webshop.Application.Services.Admin
 {
+    // Implementiert das Interface, das der Controller erwartet
     public class AdminSupplierService : IAdminSupplierService
     {
         private readonly ISupplierRepository _supplierRepository;
 
+        // Lässt sich das Repository per Dependency Injection geben
         public AdminSupplierService(ISupplierRepository supplierRepository)
         {
             _supplierRepository = supplierRepository;
         }
 
-        // HIER KOMMT DER VORHERIGE ADMINSUPPLIERSERVICE CODE HIN (GetAllSuppliersAsync, CreateSupplierAsync etc.)
-        // Hier sind Platzhalter-Implementierungen, die Sie durch den vollständigen Code ersetzen müssen:
-        public async Task<IEnumerable<SupplierDto>> GetAllSuppliersAsync() { return new List<SupplierDto>(); }
-        public async Task<SupplierDto?> GetSupplierByIdAsync(Guid id) { return null; }
-        public async Task<SupplierDto> CreateSupplierAsync(SupplierDto supplierDto) { return null; }
+        public async Task<IEnumerable<SupplierDto>> GetAllSuppliersAsync()
+        {
+            var suppliers = await _supplierRepository.GetAllSuppliersAsync();
+            // Mappt die Entity-Liste zu einer DTO-Liste für die API
+            return suppliers.Select(s => new SupplierDto
+            {
+                Id = s.Id,
+                Name = s.Name,
+                ContactPerson = s.ContactPerson,
+                Email = s.Email,
+                PhoneNumber = s.PhoneNumber,
+                AddressId = s.AddressId,
+                Notes = s.Notes
+            });
+        }
+
+        public async Task<SupplierDto?> GetSupplierByIdAsync(Guid id)
+        {
+            var supplier = await _supplierRepository.GetSupplierByIdAsync(id);
+            if (supplier == null) return null;
+
+            // Mappt die gefundene Entity zu einem DTO
+            return new SupplierDto
+            {
+                Id = supplier.Id,
+                Name = supplier.Name,
+                ContactPerson = supplier.ContactPerson,
+                Email = supplier.Email,
+                PhoneNumber = supplier.PhoneNumber,
+                AddressId = supplier.AddressId,
+                Notes = supplier.Notes
+            };
+        }
+
+        public async Task<SupplierDto> CreateSupplierAsync(SupplierDto supplierDto)
+        {
+            // Wandelt das DTO von der API in eine Datenbank-Entity um
+            var supplier = new Supplier
+            {
+                Name = supplierDto.Name,
+                ContactPerson = supplierDto.ContactPerson,
+                Email = supplierDto.Email,
+                PhoneNumber = supplierDto.PhoneNumber,
+                AddressId = supplierDto.AddressId,
+                Notes = supplierDto.Notes
+            };
+
+            await _supplierRepository.AddSupplierAsync(supplier);
+
+            // Gibt ein DTO mit der neu generierten ID zurück
+            supplierDto.Id = supplier.Id;
+            return supplierDto;
+        }
+
+        public async Task<bool> UpdateSupplierAsync(Guid id, SupplierDto supplierDto)
+        {
+            var existingSupplier = await _supplierRepository.GetSupplierByIdAsync(id);
+            if (existingSupplier == null)
+            {
+                return false; // Konnte nicht gefunden werden
+            }
+
+            // Aktualisiert die Daten der gefundenen Entity
+            existingSupplier.Name = supplierDto.Name;
+            existingSupplier.ContactPerson = supplierDto.ContactPerson;
+            existingSupplier.Email = supplierDto.Email;
+            existingSupplier.PhoneNumber = supplierDto.PhoneNumber;
+            existingSupplier.AddressId = supplierDto.AddressId;
+            existingSupplier.Notes = supplierDto.Notes;
+
+            await _supplierRepository.UpdateSupplierAsync(existingSupplier);
+            return true;
+        }
+
+        public async Task<bool> DeleteSupplierAsync(Guid id)
+        {
+            var supplier = await _supplierRepository.GetSupplierByIdAsync(id);
+            if (supplier == null)
+            {
+                return false; // Konnte nicht gefunden werden
+            }
+
+            await _supplierRepository.DeleteSupplierAsync(id);
+            return true;
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/Webshop.Application/Services/Admin/IAdminSupplierService.cs b/Webshop.Application/Services/Admin/IAdminSupplierService.cs
index e2943db..5429fd3 100644
--- a/Webshop.Application/Services/Admin/IAdminSupplierService.cs
+++ b/Webshop.Application/Services/Admin/IAdminSupplierService.cs
@@ -1,16 +1,21 @@
 // src/Webshop.Application/Services/Admin/IAdminSupplierService.cs
+
+using System; // Für Guid
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using Webshop.Application.DTOs; // SupplierDto
+using Webshop.Application.DTOs; // Für SupplierDto
 
 namespace Webshop.Application.Services.Admin
 {
     public interface IAdminSupplierService
     {
+        // Diese Methoden waren bereits vorhanden
         Task<IEnumerable<SupplierDto>> GetAllSuppliersAsync();
         Task<SupplierDto?> GetSupplierByIdAsync(Guid id);
         Task<SupplierDto> CreateSupplierAsync(SupplierDto supplierDto);
-        // Task<bool> UpdateSupplierAsync(SupplierDto supplierDto); // Beispiel für zukünftige Methode
-        // Task<bool> DeleteSupplierAsync(Guid id); // Beispiel für zukünftige Methode
+
+        // --- HIER DIE FEHLENDEN METHODEN ERGÄNZEN ---
+        Task<bool> UpdateSupplierAsync(Guid id, SupplierDto supplierDto);
+        Task<bool> DeleteSupplierAsync(Guid id);
     }
 }
\ No newline at end of file