diff --git a/STOContracts/BusinessLogicContracts/ICarLogic.cs b/STOContracts/BusinessLogicContracts/ICarLogic.cs
new file mode 100644
index 0000000..1552e5e
--- /dev/null
+++ b/STOContracts/BusinessLogicContracts/ICarLogic.cs
@@ -0,0 +1,15 @@
+using STOContracts.BindingModels;
+using STOContracts.SearchModels;
+using STOContracts.ViewModels;
+
+namespace STOContracts.BusinessLogicsContracts
+{
+    public interface ICarLogic
+    {
+        List<CarViewModel>? ReadList(CarSearchModel? model);
+        CarViewModel? ReadElement(CarSearchModel model);
+        bool Create(CarBindingModel model);
+        bool Update(CarBindingModel model);
+        bool Delete(CarBindingModel model);
+    }
+}
diff --git a/STOContracts/BusinessLogicContracts/ICarPartLogic.cs b/STOContracts/BusinessLogicContracts/ICarPartLogic.cs
new file mode 100644
index 0000000..ce37030
--- /dev/null
+++ b/STOContracts/BusinessLogicContracts/ICarPartLogic.cs
@@ -0,0 +1,20 @@
+using STOContracts.BindingModels;
+using STOContracts.SearchModels;
+using STOContracts.ViewModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace STOContracts.BusinessLogicContracts
+{
+    public interface ICarPartLogic
+    {
+        List<CarPartViewModel>? ReadList(CarPartSearchModel? model);
+        CarPartViewModel? ReadElement(CarPartSearchModel model);
+        bool Create(CarPartBindingModel model);
+        bool Update(CarPartBindingModel model);
+        bool Delete(CarPartBindingModel model);
+    }
+}
diff --git a/STOContracts/BusinessLogicContracts/IClientLogic.cs b/STOContracts/BusinessLogicContracts/IClientLogic.cs
new file mode 100644
index 0000000..ea35ed1
--- /dev/null
+++ b/STOContracts/BusinessLogicContracts/IClientLogic.cs
@@ -0,0 +1,20 @@
+using STOContracts.BindingModels;
+using STOContracts.SearchModels;
+using STOContracts.ViewModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace STOContracts.BusinessLogicContracts
+{
+    public interface IClientLogic
+    {
+        List<ClientViewModel>? ReadList(ClientSearchModel? model);
+        ClientViewModel? ReadElement(ClientSearchModel model);
+        bool Create(ClientBindingModel model);
+        bool Update(ClientBindingModel model);
+        bool Delete(ClientBindingModel model);
+    }
+}
diff --git a/STOContracts/BusinessLogicContracts/IServiceLogic.cs b/STOContracts/BusinessLogicContracts/IServiceLogic.cs
new file mode 100644
index 0000000..b3a916a
--- /dev/null
+++ b/STOContracts/BusinessLogicContracts/IServiceLogic.cs
@@ -0,0 +1,15 @@
+using STOContracts.BindingModels;
+using STOContracts.SearchModels;
+using STOContracts.ViewModels;
+
+namespace STOContracts.BusinessLogicsContracts
+{
+    public interface IServiceLogic
+    {
+        List<ServiceViewModel>? ReadList(ServiceSearchModel? model);
+        ServiceViewModel? ReadElement(ServiceSearchModel model);
+        bool Create(ServiceBindingModel model);
+        bool Update(ServiceBindingModel model);
+        bool Delete(ServiceBindingModel model);
+    }
+}
\ No newline at end of file
diff --git a/STOContracts/BusinessLogicContracts/ITechnicalWorkLogic.cs b/STOContracts/BusinessLogicContracts/ITechnicalWorkLogic.cs
new file mode 100644
index 0000000..4d1bba2
--- /dev/null
+++ b/STOContracts/BusinessLogicContracts/ITechnicalWorkLogic.cs
@@ -0,0 +1,15 @@
+using STOContracts.BindingModels;
+using STOContracts.SearchModels;
+using STOContracts.ViewModels;
+
+namespace STOContracts.BusinessLogicsContracts
+{
+    public interface ITechnicalWorkLogic
+    {
+        List<TechnicalWorkViewModel>? ReadList(TechnicalWorkSearchModel? model);
+        TechnicalWorkViewModel? ReadElement(TechnicalWorkSearchModel model);
+        bool Create(TechnicalWorkBindingModel model);
+        bool Update(TechnicalWorkBindingModel model);
+        bool Delete(TechnicalWorkBindingModel model);
+    }
+}