diff --git a/DoliMiddlewareApi/Program.cs b/DoliMiddlewareApi/Program.cs
index e43ad64..0b9557a 100644
--- a/DoliMiddlewareApi/Program.cs
+++ b/DoliMiddlewareApi/Program.cs
@@ -22,7 +22,8 @@ builder.Services.AddSwaggerGen();
 
 
 // Typed Client - Inyecta HttpClient directamente en DolibarrApiClient
-builder.Services.AddHttpClient<DolibarrApiClient>(client =>
+// Registra la interfaz para poder hacer mock en tests
+builder.Services.AddHttpClient<IDolibarrApiClient, DolibarrApiClient>(client =>
 {
     client.BaseAddress = new Uri(builder.Configuration["Dolibarr:ApiUrl"]!);
     client.DefaultRequestHeaders.Add("DOLAPIKEY", builder.Configuration["Dolibarr:ApiKey"]!);
diff --git a/DoliMiddlewareApi/Services/Clients/DolibarrApiClient.cs b/DoliMiddlewareApi/Services/Clients/DolibarrApiClient.cs
index e1f23a0..f87b200 100644
--- a/DoliMiddlewareApi/Services/Clients/DolibarrApiClient.cs
+++ b/DoliMiddlewareApi/Services/Clients/DolibarrApiClient.cs
@@ -3,7 +3,7 @@ using DoliMiddlewareApi.Exceptions;
 
 namespace DoliMiddlewareApi.Services.Clients;
 
-public class DolibarrApiClient
+public class DolibarrApiClient : IDolibarrApiClient
 {
     private readonly HttpClient _httpClient;
 
diff --git a/DoliMiddlewareApi/Services/Clients/IDolibarrApiClient.cs b/DoliMiddlewareApi/Services/Clients/IDolibarrApiClient.cs
new file mode 100644
index 0000000..07c7ec1
--- /dev/null
+++ b/DoliMiddlewareApi/Services/Clients/IDolibarrApiClient.cs
@@ -0,0 +1,9 @@
+namespace DoliMiddlewareApi.Services.Clients;
+
+public interface IDolibarrApiClient
+{
+    Task<T> GetResourceAsync<T>(string endpoint) where T : class;
+    Task<List<T>> GetCollectionAsync<T>(string endpoint) where T : class;
+    Task<string> PostAsync(string endpoint, object requestBody);
+    Task<string> PutAsync(string endpoint, object requestBody);
+}
diff --git a/DoliMiddlewareApi/Services/InvoiceService.cs b/DoliMiddlewareApi/Services/InvoiceService.cs
index f00e2dc..73a8201 100644
--- a/DoliMiddlewareApi/Services/InvoiceService.cs
+++ b/DoliMiddlewareApi/Services/InvoiceService.cs
@@ -10,9 +10,9 @@ namespace DoliMiddlewareApi.Services;
 
 public class InvoiceService
 {
-    private readonly DolibarrApiClient _apiClient;
+    private readonly IDolibarrApiClient _apiClient;
 
-    public InvoiceService(DolibarrApiClient apiClient)
+    public InvoiceService(IDolibarrApiClient apiClient)
     {
         _apiClient = apiClient;
     }