diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/ClientDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/ClientDataModel.cs
new file mode 100644
index 0000000..8669f11
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/ClientDataModel.cs
@@ -0,0 +1,33 @@
+using System.Text.RegularExpressions;
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class ClientDataModel(string id, string fio, string email) : IValidation
+{
+    public string Id { get; private set; } = id;
+
+    public string FIO { get; private set; } = fio;
+
+    public string Email { get; private set; } = email;
+
+    public void Validate()
+    {
+        if (Id.IsEmpty())
+            throw new ValidationException("Field Id is empty");
+
+        if (!Id.IsGuid())
+            throw new ValidationException("The value in the field Id is not a unique identifier");
+
+        if (FIO.IsEmpty())
+            throw new ValidationException("Field FIO is empty");
+
+        if (Email.IsEmpty())
+            throw new ValidationException("Field Email is empty");
+
+        if (!Regex.IsMatch(Email, @"^\S+@\S+\.\S+$"))
+            throw new ValidationException("Field Email is not an email address");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/ComponentDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/ComponentDataModel.cs
new file mode 100644
index 0000000..fe8ddaa
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/ComponentDataModel.cs
@@ -0,0 +1,38 @@
+using TheCyclopsContracts.Enums;
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class ComponentDataModel(string id, string componentName,
+    ComponentType componentType, double price, bool isDeleted) : IValidation
+{
+    public string Id { get; private set; } = id;
+
+    public string ComponentName { get; private set; } = componentName;
+
+    public ComponentType ComponentType { get; private set; } = componentType;
+
+    public double Price { get; private set; } = price;
+
+    public bool IsDeleted { get; private set; } = isDeleted;
+
+    public void Validate()
+    {
+        if (Id.IsEmpty())
+            throw new ValidationException("Field Id is empty");
+
+        if (!Id.IsGuid())
+            throw new ValidationException("The value in the field Id is not a unique identifier");
+
+        if (ComponentName.IsEmpty())
+            throw new ValidationException("Field ComponentName is empty");
+
+        if (ComponentType == ComponentType.None)
+            throw new ValidationException("Field ComponentType is empty");
+
+        if (Price <= 0)
+            throw new ValidationException("Field Price is less than or equal to 0");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/EmployeeDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/EmployeeDataModel.cs
new file mode 100644
index 0000000..6e1f24e
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/EmployeeDataModel.cs
@@ -0,0 +1,47 @@
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class EmployeeDataModel(string id, string fio, string postId, DateTime birthDate, DateTime employmentDate, bool isDeleted) : IValidation
+{
+    public string Id { get; private set; } = id;
+
+    public string FIO { get; private set; } = fio;
+
+    public string PostId { get; private set; } = postId;
+
+    public DateTime BirthDate { get; private set; } = birthDate;
+
+    public DateTime EmploymentDate { get; private set; } = employmentDate;
+
+    public bool IsDeleted { get; private set; } = isDeleted;
+
+    public void Validate()
+    {
+        if (Id.IsEmpty())
+            throw new ValidationException("Field Id is empty");
+
+        if (!Id.IsGuid())
+            throw new ValidationException("The value in the field Id is not a unique identifier");
+
+        if (FIO.IsEmpty())
+            throw new ValidationException("Field FIO is empty");
+
+        if (PostId.IsEmpty())
+            throw new ValidationException("Field PostId is empty");
+
+        if (!PostId.IsGuid())
+            throw new ValidationException("The value in the field PostId is not a unique identifier");
+
+        if (BirthDate.Date > DateTime.Now.AddYears(-16).Date)
+            throw new ValidationException($"Minors cannot be hired (BirthDate = {BirthDate.ToShortDateString()})");
+
+        if (EmploymentDate.Date < BirthDate.Date)
+            throw new ValidationException("The date of employment cannot be less than the date of birth");
+
+        if ((EmploymentDate - BirthDate).TotalDays / 365 < 16)
+            throw new ValidationException($"Minors cannot be hired (EmploymentDate - {EmploymentDate.ToShortDateString()}, BirthDate - {BirthDate.ToShortDateString()})");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationComponentDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationComponentDataModel.cs
new file mode 100644
index 0000000..baf7f7d
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationComponentDataModel.cs
@@ -0,0 +1,33 @@
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class InstallationComponentDataModel(string installationId,
+    string componentId, int count) : IValidation
+{
+    public string InstallationId { get; private set; } = installationId;
+
+    public string ComponentId { get; private set; } = componentId;
+
+    public int Count { get; private set; } = count;
+
+    public void Validate()
+    {
+        if (InstallationId.IsEmpty())
+            throw new ValidationException("Field InstallationId is empty");
+
+        if (!InstallationId.IsGuid())
+            throw new ValidationException("The value in the field InstallationId is not a unique identifier");
+
+        if (ComponentId.IsEmpty())
+            throw new ValidationException("Field ComponentId is empty");
+
+        if (!ComponentId.IsGuid())
+            throw new ValidationException("The value in the field ComponentId is not a unique identifier");
+
+        if (Count <= 0)
+            throw new ValidationException("Field Count is less than or equal to 0");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationDataModel.cs
new file mode 100644
index 0000000..9e39d32
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/InstallationDataModel.cs
@@ -0,0 +1,55 @@
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class InstallationDataModel(string id, string employeeId, string? clientId, 
+    DateTime installationDate, double installationPrice, double sum, bool isCanceled, 
+    List<InstallationComponentDataModel> components) : IValidation
+{
+    public string Id { get; private set; } = id;
+
+    public string EmployeeId { get; private set; } = employeeId;
+
+    public string? ClientId { get; private set; } = clientId;
+
+    public DateTime SaleDate { get; private set; } = DateTime.UtcNow;
+
+    public DateTime InstallationDate { get; private set; } = installationDate;
+
+    public double InstallationPrice { get; private set; } = installationPrice;
+
+    public double Sum { get; private set; } = sum;
+
+    public bool IsCanceled { get; private set; } = isCanceled;
+
+    public List<InstallationComponentDataModel> Components { get; private set; } = components;
+
+    public void Validate()
+    {
+        if (Id.IsEmpty())
+            throw new ValidationException("Field Id is empty");
+
+        if (!Id.IsGuid())
+            throw new ValidationException("The value in the field Id is not a unique identifier");
+
+        if (EmployeeId.IsEmpty())
+            throw new ValidationException("Field EmployeeId is empty");
+
+        if (!EmployeeId.IsGuid())
+            throw new ValidationException("The value in the field EmployeeId is not a unique identifier");
+
+        if (!ClientId?.IsGuid() ?? !ClientId?.IsEmpty() ?? false)
+            throw new ValidationException("The value in the field ClientId is not a unique identifier");
+
+        if (InstallationPrice <= 0)
+            throw new ValidationException("Field InstallationPrice is less than or equal to 0");
+
+        if (Sum <= 0)
+            throw new ValidationException("Field Sum is less than or equal to 0");
+
+        if ((Components?.Count ?? 0) == 0)
+            throw new ValidationException("The sale must include components");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/PostDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/PostDataModel.cs
new file mode 100644
index 0000000..6025af1
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/PostDataModel.cs
@@ -0,0 +1,46 @@
+using TheCyclopsContracts.Enums;
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class PostDataModel(string id, string PostId, string postName, PostType postType, double salary, bool isActual, DateTime changeDate)
+{
+    public string Id { get; private set; } = id;
+
+    public string PostId { get; private set; } = PostId;
+
+    public string PostName { get; private set; } = postName;
+
+    public PostType PostType { get; private set; } = postType;
+
+    public double Salary { get; private set; } = salary;
+
+    public bool IsActual { get; private set; } = isActual;
+
+    public DateTime ChangeDate { get; private set; } = changeDate;
+
+    public void Validate()
+    {
+        if (Id.IsEmpty())
+            throw new ValidationException("Field Id is empty");
+
+        if (!Id.IsGuid())
+            throw new ValidationException("The value in the field Id is not a unique identifier");
+
+        if (PostId.IsEmpty())
+            throw new ValidationException("Field PostId is empty");
+
+        if (!PostId.IsGuid())
+            throw new ValidationException("The value in the field PostId is not a unique identifier");
+
+        if (PostName.IsEmpty())
+            throw new ValidationException("Field PostName is empty");
+
+        if (PostType == PostType.None)
+            throw new ValidationException("Field PostType is empty");
+
+        if (Salary <= 0)
+            throw new ValidationException("Field Salary is empty");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/DataModels/SalaryDataModel.cs b/TheCyclopsProject/TheCyclopsContracts/DataModels/SalaryDataModel.cs
new file mode 100644
index 0000000..d45c4c4
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/DataModels/SalaryDataModel.cs
@@ -0,0 +1,26 @@
+using TheCyclopsContracts.Exceptions;
+using TheCyclopsContracts.Extensions;
+using TheCyclopsContracts.Infrastructure;
+
+namespace TheCyclopsContracts.DataModels;
+
+public class SalaryDataModel(string employeeId, DateTime salaryDate, double employeeSalary) : IValidation
+{
+    public string EmployeeId { get; private set; } = employeeId;
+
+    public DateTime SalaryDate { get; private set; } = salaryDate;
+
+    public double Salary { get; private set; } = employeeSalary;
+
+    public void Validate()
+    {
+        if (EmployeeId.IsEmpty())
+            throw new ValidationException("Field EmployeeId is empty");
+
+        if (!EmployeeId.IsGuid())
+            throw new ValidationException("The value in the field EmployeeId is not a unique identifier");
+
+        if (Salary <= 0)
+            throw new ValidationException("Field Salary is less than or equal to 0");
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/Enums/ComponentType.cs b/TheCyclopsProject/TheCyclopsContracts/Enums/ComponentType.cs
new file mode 100644
index 0000000..ca2cb65
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/Enums/ComponentType.cs
@@ -0,0 +1,11 @@
+namespace TheCyclopsContracts.Enums;
+
+public enum ComponentType
+{
+    None = 0,
+    Camera = 1,
+    Sensor = 2,
+    ContropPanel = 3,
+    Cable = 4,
+    Other = 5
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/Enums/PostType.cs b/TheCyclopsProject/TheCyclopsContracts/Enums/PostType.cs
new file mode 100644
index 0000000..51e142a
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/Enums/PostType.cs
@@ -0,0 +1,10 @@
+namespace TheCyclopsContracts.Enums;
+
+public enum PostType
+{
+    None = 0,
+    Designer = 1,
+    Installer = 2,
+    Seller = 3,
+    Administrator = 4
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/Exceptions/ValidationException.cs b/TheCyclopsProject/TheCyclopsContracts/Exceptions/ValidationException.cs
new file mode 100644
index 0000000..b601647
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/Exceptions/ValidationException.cs
@@ -0,0 +1,5 @@
+namespace TheCyclopsContracts.Exceptions;
+
+public class ValidationException(string message) : Exception(message)
+{
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/Extensions/StringExtension.cs b/TheCyclopsProject/TheCyclopsContracts/Extensions/StringExtension.cs
new file mode 100644
index 0000000..5617a8f
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/Extensions/StringExtension.cs
@@ -0,0 +1,14 @@
+namespace TheCyclopsContracts.Extensions;
+
+public static class StringExtension
+{
+    public static bool IsEmpty(this string str)
+    {
+        return string.IsNullOrEmpty(str);
+    }
+
+    public static bool IsGuid(this string str)
+    {
+        return Guid.TryParse(str, out _);
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsContracts/Infrastructure/IValidation.cs b/TheCyclopsProject/TheCyclopsContracts/Infrastructure/IValidation.cs
new file mode 100644
index 0000000..ec8eb55
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsContracts/Infrastructure/IValidation.cs
@@ -0,0 +1,6 @@
+namespace TheCyclopsContracts.Infrastructure;
+
+public interface IValidation
+{
+    void Validate();
+}