diff --git a/Govor.API.Tests/IntegrationTests/EF/Repositories/AdminsRepositoryTests.cs b/Govor.API.Tests/IntegrationTests/EF/Repositories/AdminsRepositoryTests.cs
index ddb9337..42a85d6 100644
--- a/Govor.API.Tests/IntegrationTests/EF/Repositories/AdminsRepositoryTests.cs
+++ b/Govor.API.Tests/IntegrationTests/EF/Repositories/AdminsRepositoryTests.cs
@@ -91,6 +91,7 @@ public class AdminsRepositoryTests
     [Test]
     public async Task Given_InvalidUserId_When_GetByIdAsync_Should_Throw_NotFoundByKeyException()
     {
+        // Arrange 
         await using var context = new GovorDbContext(_options);
         var repository = new AdminsRepository(context, _validator);
         
diff --git a/Govor.API.Tests/IntegrationTests/EF/Repositories/InvitesRepositoryTests.cs b/Govor.API.Tests/IntegrationTests/EF/Repositories/InvitesRepositoryTests.cs
new file mode 100644
index 0000000..59b18ee
--- /dev/null
+++ b/Govor.API.Tests/IntegrationTests/EF/Repositories/InvitesRepositoryTests.cs
@@ -0,0 +1,244 @@
+using AutoFixture;
+using Govor.Core.Infrastructure.Validators;
+using Govor.Core.Models;
+using Govor.Data;
+using Govor.Data.Repositories;
+using Govor.Data.Repositories.Exceptions;
+using Microsoft.EntityFrameworkCore;
+
+namespace Govor.API.Tests.IntegrationTests.EF.Repositories;
+
+[TestFixture]
+public class InvitesRepositoryTests
+{
+    private Fixture _fixture;
+    private DbContextOptions<GovorDbContext> _options;
+    private IObjectValidator<Invitation> _validator = new InvitationValidator();
+    private int _testIteration = 0;
+    
+    [SetUp]
+    public void Setup()
+    {
+        _fixture = new Fixture();
+        
+        _fixture.Behaviors
+            .OfType<ThrowingRecursionBehavior>()
+            .ToList()
+            .ForEach(b => _fixture.Behaviors.Remove(b));
+
+        _fixture.Behaviors.Add(new OmitOnRecursionBehavior());
+        
+        _options = new DbContextOptionsBuilder<GovorDbContext>()
+            .UseInMemoryDatabase(databaseName: $"DbGovor_{nameof(InvitesRepositoryTests)}_{_testIteration}")
+            .Options;
+        _testIteration += 1;
+    }
+    
+    [Test]
+    public async Task Given_NotEmptyDbSet_When_GetAllAsync_Then_Invites_Are_Returned()
+    {
+        // Arrange 
+        var random = new Random();
+        var invitations = _fixture.CreateMany<Invitation>(random.Next(3, 10)).ToList();
+
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        context.Invitations.AddRange(invitations);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await repository.GetAllAsync();
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Count(), Is.EqualTo(invitations.Count()));
+        Assert.That(result, Is.EquivalentTo(invitations));
+    }
+    
+    [Test]
+    public async Task Given_EmptyDbSet_When_GetAllAsync_Should_Throw_NotFoundException()
+    {
+        // Arrange 
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<NotFoundException>(async () => await repository.GetAllAsync());
+    }
+
+    [Test]
+    public async Task Given_ValidInvitesId_When_FindByIdAsync_Then_Invites_Are_Returned()
+    {
+        // Arrange 
+        var invitation = _fixture.Create<Invitation>();
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        context.Invitations.Add(invitation);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await repository.FindByIdAsync(invitation.Id);
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Id, Is.EqualTo(invitation.Id));
+    }
+    
+    [Test]
+    public async Task Given_InvalidInvitesId_When_FindByIdAsync_Should_Throw_NotFoundByKeyException()
+    {
+        // Arrange 
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<NotFoundByKeyException<Guid>>(async () => await repository.FindByIdAsync(Guid.Empty));
+    }
+    
+    [Test]
+    public async Task Given_ValidInvitesCode_When_FindByCodeAsync_Then_Invites_Are_Returned()
+    {
+        // Arrange 
+        var invitation = _fixture.Create<Invitation>();
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        context.Invitations.Add(invitation);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await repository.FindByCodeAsync(invitation.Code);
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Id, Is.EqualTo(invitation.Id));
+    }
+    
+    [Test]
+    public async Task Given_InvalidCode_When_FindByCodeAsync_Should_Throw_NotFoundByKeyException()
+    {
+        // Arrange 
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<NotFoundByKeyException<string>>(async () => await repository.FindByCodeAsync(_fixture.Create<string>()));
+    }
+    
+    [Test]
+    public async Task Given_ValidAdminInvites_When_FindAdminsInvitesAsync_Then_Invites_Are_Returned()
+    {
+        // Arrange 
+        var random = new Random();
+        var invitations = _fixture.CreateMany<Invitation>(random.Next(3, 10)).ToList();
+        
+        foreach (var inv in invitations)
+        {
+            inv.IsAdmin = true;
+        }
+        
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        context.Invitations.AddRange(invitations);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await repository.FindAdminsInvitesAsync();
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Count(), Is.EqualTo(invitations.Count()));
+        Assert.That(result, Is.EquivalentTo(invitations));
+    }
+    
+    [Test]
+    public async Task Given_InvalidAdminsInvites_When_FindAdminsInvitesAsync_Should_Throw_NotFoundByKeyException()
+    {
+        // Arrange 
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<NotFoundByKeyException<bool>>(async () => await repository.FindAdminsInvitesAsync());
+    }
+    
+    [Test]
+    public async Task Given_ValidAdmin_When_AddAsync_Then_Added()
+    {
+        // Arrange
+        var invitation = _fixture.Create<Invitation>();
+        invitation.Code = string.Join("", _fixture.CreateMany<char>(12));
+        invitation.EndDate = invitation.DateCreated.AddHours(1);
+        
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+    
+        // Act 
+        await repository.AddAsync(invitation);
+        
+        // Assert 
+        Assert.That(context.Invitations.Count, Is.EqualTo(1));
+        Assert.That(context.Invitations.First(), Is.EqualTo(invitation));
+    }
+    
+    [Test]
+    public async Task Given_InvalidAdmin_When_AddAsync_Should_Throw_AdditionException()
+    {
+        // Arrange
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<AdditionException>(async () => await repository.AddAsync(default));
+    }
+    
+    [Test]
+    public async Task Given_NotExistInvitesCode_When_Exist_Then_Returns_False()
+    {
+        // Arrange
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act 
+        var result = repository.Exist(Guid.NewGuid());
+        
+        Assert.That(result, Is.False);
+    }
+    
+    [Test]
+    public async Task Given_ExistInvitesCode_When_Exist_Then_Returns_False()
+    {
+        // Arrange
+        var invitation = _fixture.Create<Invitation>();
+        
+        invitation.Code = string.Join("", _fixture.CreateMany<char>(12));
+        invitation.EndDate = invitation.DateCreated.AddHours(1);
+        
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        context.Invitations.Add(invitation);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = repository.Exist(invitation.Id);
+        var result2 = repository.Exist(invitation);
+        
+        Assert.That(result, Is.True);
+        Assert.That(result2, Is.True);
+    }
+    
+    [Test]
+    public async Task Given_InvalidInvites_When_Exist_Then_Returns_False()
+    {
+        // Arrange
+        await using var context = new GovorDbContext(_options);
+        var repository = new InvitesRepository(context, _validator);
+        
+        // Act & Assert 
+        Assert.Throws<InvalidObjectException<Invitation>>(() => repository.Exist(default(Invitation)));
+    }
+}
\ No newline at end of file
diff --git a/Govor.API.Tests/UnitTests/Infrastructure/Validators/InvitationValidatorTests.cs b/Govor.API.Tests/UnitTests/Infrastructure/Validators/InvitationValidatorTests.cs
index 7a2a9b4..68e71e5 100644
--- a/Govor.API.Tests/UnitTests/Infrastructure/Validators/InvitationValidatorTests.cs
+++ b/Govor.API.Tests/UnitTests/Infrastructure/Validators/InvitationValidatorTests.cs
@@ -89,4 +89,16 @@ public class InvitationValidatorTests
         Assert.Throws<InvalidObjectException<Invitation>>( () => _messageValidator.Validate(invitation));
         Assert.That(_messageValidator.TryValidate(invitation), Is.False);
     }
+    
+    [Test]
+    public void Given_InvalidCode_When_Exist_Then_Returns_False()
+    {
+        // Arrange 
+        var invitation = _fixture.Create<Invitation>();
+        invitation.Code = string.Empty;
+        
+        // Act & Assert 
+        Assert.Throws<InvalidObjectException<Invitation>>( () => _messageValidator.Validate(invitation));
+        Assert.That(_messageValidator.TryValidate(invitation), Is.False);
+    }
 }
\ No newline at end of file
diff --git a/Govor.API/Services/Authentication/AuthService.cs b/Govor.API/Services/Authentication/AuthService.cs
index 2c662dc..9ea80a5 100644
--- a/Govor.API/Services/Authentication/AuthService.cs
+++ b/Govor.API/Services/Authentication/AuthService.cs
@@ -38,7 +38,7 @@ public class AuthService : IAccountService
             throw new UserAlreadyExistException(name);
 
         // 2. Проверка валидности инвайта
-        var invite = await _invitesRepository.GetByCodeAsync(inviteCode);
+        var invite = await _invitesRepository.FindByCodeAsync(inviteCode);
 
         // 3. Генерация пароля
         var passwordHash = _passwordHasher.Hash(password);
diff --git a/Govor.API/Services/Authentication/JwtService.cs b/Govor.API/Services/Authentication/JwtService.cs
index f827790..9a62426 100644
--- a/Govor.API/Services/Authentication/JwtService.cs
+++ b/Govor.API/Services/Authentication/JwtService.cs
@@ -22,7 +22,7 @@ public class JwtService : IJwtService
     
     public string GenerateJwtToken(User user)
     {
-        var invite = _invitesRepository.GetByIdAsync(user.InviteId).Result;
+        var invite = _invitesRepository.FindByIdAsync(user.InviteId).Result;
         
         var claims = new[]
         {
diff --git a/Govor.Core/DTOs/RegistrationDto.cs b/Govor.Core/DTOs/RegistrationDto.cs
index 4216c80..dc32a91 100644
--- a/Govor.Core/DTOs/RegistrationDto.cs
+++ b/Govor.Core/DTOs/RegistrationDto.cs
@@ -1,5 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 using Govor.Core.Infrastructure.Validators;
+using Govor.Core.Models;
 
 namespace Govor.Core.DTOs;
 
@@ -13,6 +14,6 @@ public record RegistrationDto
     [Required]
     [MinLength(8)]
     public string Password { get; init; }
-    [MinLength(8)]
+    [MinLength(InvitationValidator.MIN_INVITATION_LENGTH)]
     public string InviteLink { get; init; }
 }
\ No newline at end of file
diff --git a/Govor.Core/Infrastructure/Validators/InvitationValidator.cs b/Govor.Core/Infrastructure/Validators/InvitationValidator.cs
index 813da99..069fe1d 100644
--- a/Govor.Core/Infrastructure/Validators/InvitationValidator.cs
+++ b/Govor.Core/Infrastructure/Validators/InvitationValidator.cs
@@ -4,6 +4,7 @@ namespace Govor.Core.Infrastructure.Validators;
 
 public class InvitationValidator : IObjectValidator<Invitation>
 {
+    public const int MIN_INVITATION_LENGTH = 10;
     public void Validate(Invitation inv)
     {
         try
@@ -18,6 +19,8 @@ public class InvitationValidator : IObjectValidator<Invitation>
                 throw new ArgumentException("EndDate cannot be less than StartDate", nameof(inv.EndDate));
             if(inv.MaxParticipants <= 0)
                 throw new ArgumentException("MaxParticipants cannot be less than 0", nameof(inv.MaxParticipants));
+            if(inv.Code == string.Empty || inv.Code.Length < MIN_INVITATION_LENGTH)
+                throw new ArgumentException($"Code cannot be empty or less then {MIN_INVITATION_LENGTH}", nameof(inv.Code));
         }
         catch (Exception ex)
         {
diff --git a/Govor.Core/Models/Invitation.cs b/Govor.Core/Models/Invitation.cs
index 5e3bf01..a53c29e 100644
--- a/Govor.Core/Models/Invitation.cs
+++ b/Govor.Core/Models/Invitation.cs
@@ -4,9 +4,22 @@ public class Invitation
 {
     public Guid Id { get; set; }
     public bool IsAdmin { get; set; }
+    public string Code { get; set; }
     public string Description { get; set; }
     public DateTime DateCreated { get; set; }
     public DateTime EndDate { get; set; }
     public int MaxParticipants { get; set; }
     public List<User> Users { get; set; } = new List<User>();
+
+    public override bool Equals(object? obj)
+    {
+        var invitation = obj as Invitation ?? throw new InvalidCastException();
+
+        return Id == invitation.Id &&
+               IsAdmin == invitation.IsAdmin &&
+               Description == invitation.Description &&
+               DateCreated == invitation.DateCreated &&
+               EndDate == invitation.EndDate &&
+               MaxParticipants == invitation.MaxParticipants;
+    }
 }
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Admins/IAdminsWriter.cs b/Govor.Core/Repositories/Admins/IAdminsWriter.cs
index 2355013..d34d582 100644
--- a/Govor.Core/Repositories/Admins/IAdminsWriter.cs
+++ b/Govor.Core/Repositories/Admins/IAdminsWriter.cs
@@ -6,5 +6,5 @@ public interface IAdminsWriter
 {
     Task AddAsync(Admin admin);
     Task UpdateAsync(Admin admin);
-    Task DeleteAsync(Guid admin);
+    Task RemoveAsync(Guid admin);
 }
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Invaites/IInvitesReader.cs b/Govor.Core/Repositories/Invaites/IInvitesReader.cs
index 94e9493..85cb34d 100644
--- a/Govor.Core/Repositories/Invaites/IInvitesReader.cs
+++ b/Govor.Core/Repositories/Invaites/IInvitesReader.cs
@@ -5,7 +5,7 @@ namespace Govor.Core.Repositories.Invaites;
 public interface IInvitesReader
 {
     Task<List<Invitation>> GetAllAsync();
-    Task<Invitation> GetByIdAsync(Guid id);
-    Task<Invitation> GetByCodeAsync(string code);
-    Task<List<Invitation>> GetAdminsInvitesAsync();
+    Task<Invitation> FindByIdAsync(Guid id);
+    Task<Invitation> FindByCodeAsync(string code);
+    Task<List<Invitation>> FindAdminsInvitesAsync();
 }
\ No newline at end of file
diff --git a/Govor.Data/Repositories/AdminsRepository.cs b/Govor.Data/Repositories/AdminsRepository.cs
index 0482504..0e5783b 100644
--- a/Govor.Data/Repositories/AdminsRepository.cs
+++ b/Govor.Data/Repositories/AdminsRepository.cs
@@ -72,7 +72,7 @@ public class AdminsRepository(GovorDbContext context, IObjectValidator<Admin> va
         }
     }
 
-    public async Task DeleteAsync(Guid admin)
+    public async Task RemoveAsync(Guid admin)
     {
         try
         {
diff --git a/Govor.Data/Repositories/InvitesRepository.cs b/Govor.Data/Repositories/InvitesRepository.cs
index 7b18448..374e697 100644
--- a/Govor.Data/Repositories/InvitesRepository.cs
+++ b/Govor.Data/Repositories/InvitesRepository.cs
@@ -1,6 +1,9 @@
+using Govor.Core.Infrastructure.Extensions;
 using Govor.Core.Infrastructure.Validators;
 using Govor.Core.Models;
 using Govor.Core.Repositories.Invaites;
+using Govor.Data.Repositories.Exceptions;
+using Microsoft.EntityFrameworkCore;
 
 namespace Govor.Data.Repositories;
 
@@ -17,46 +20,124 @@ public class InvitesRepository : IInvitesRepository
     
     public async Task<List<Invitation>> GetAllAsync()
     {
-        throw new NotImplementedException();
+        return await _context.Invitations
+            .AsNoTracking()
+            .Include(i => i.Users)
+            .ToListOrThrowIfEmpty(new NotFoundException("Database is empty"));
     }
 
-    public Task<Invitation> GetByIdAsync(Guid id)
+    public async Task<Invitation> FindByIdAsync(Guid id)
     {
-        throw new NotImplementedException();
+        return await _context.Invitations
+            .AsNoTracking()
+            .Include(i => i.Users)
+            .FirstOrDefaultAsync(i => i.Id == id)
+            ?? throw new NotFoundByKeyException<Guid>(id, "Invitation with given id does not exist");
     }
 
-    public Task<Invitation> GetByCodeAsync(string code)
+    public async Task<Invitation> FindByCodeAsync(string code)
     {
-        throw new NotImplementedException();
+        return await _context.Invitations
+            .AsNoTracking()
+            .Include(i => i.Users)
+            .FirstOrDefaultAsync(i => i.Code == code)
+            ?? throw new NotFoundByKeyException<string>(code, "Invitation with given code does not exist");
     }
 
-    public Task<List<Invitation>> GetAdminsInvitesAsync()
+    public async Task<List<Invitation>> FindAdminsInvitesAsync()
     {
-        throw new NotImplementedException();
+        return await _context.Invitations
+            .AsNoTracking()
+            .Include(i => i.Users)
+            .Where(i => i.IsAdmin)
+            .ToListOrThrowIfEmpty(new NotFoundByKeyException<bool>(true, "Admins invites do not exist"));
     }
 
-    public Task AddAsync(Invitation invitation)
+    public async Task AddAsync(Invitation invitation)
     {
-        throw new NotImplementedException();
+        try
+        {
+            _validator.Validate(invitation);
+
+            _context.Invitations.Add(invitation);
+            await _context.SaveChangesAsync();
+        }
+        catch (InvalidObjectException<Admin> ex)
+        {
+            throw new AdditionException("Invitation with given data invalid", ex);
+        }
+        catch (Exception ex)
+        {
+            throw new AdditionException("Cannot add invitation", ex);
+        };
     }
 
-    public Task UpdateAsync(Invitation invitation)
+    public async Task UpdateAsync(Invitation invitation)
     {
-        throw new NotImplementedException();
+        try
+        {
+            _validator.Validate(invitation);
+
+            var rowsAffected = await _context.Invitations
+                .Where(a => a.Id == invitation.Id)
+                .ExecuteUpdateAsync(u => u
+                    .SetProperty(i => i.IsAdmin, invitation.IsAdmin)
+                    .SetProperty(i => i.Code, invitation.Code)
+                    .SetProperty(i => i.Description, invitation.Description)
+                    .SetProperty(i => i.DateCreated, invitation.DateCreated)
+                    .SetProperty(i => i.EndDate, invitation.EndDate)
+                    .SetProperty(i => i.MaxParticipants, invitation.MaxParticipants)
+                    .SetProperty(i => i.Users, invitation.Users)
+                );
+
+            if (rowsAffected == 0)
+                throw new NotFoundByKeyException<Guid>(invitation.Id, "Invitation with given data invalid");
+        }
+        catch (NotFoundByKeyException<Guid> ex)
+        {
+            throw new UpdateException($"Not found invitation by given id {invitation.Id}", ex);
+        }
+        catch (Exception ex)
+        {
+            throw new UpdateException($"Error when updating the invitation {invitation.Id}", ex);
+        }
     }
 
-    public Task RemoveAsync(Invitation invitation)
+    public async Task RemoveAsync(Invitation invitation)
     {
-        throw new NotImplementedException();
+        try
+        {
+            var result = await FindByIdAsync(invitation.Id);
+
+            _context.Invitations.Remove(result);
+            await _context.SaveChangesAsync();
+        }
+        catch (NotFoundByKeyException<Guid> ex)
+        {
+            throw new RemoveException($"Not found invitation by given id {invitation.Id}", ex);
+        }
+        catch (Exception ex)
+        {
+            throw new RemoveException("Error when removing the invitation", ex);
+        }
     }
 
     public bool Exist(Invitation invitation)
     {
-        throw new NotImplementedException();
+        _validator.Validate(invitation);
+        return _context.Invitations.Any(i => i.Id == invitation.Id && 
+                                             i.Code == invitation.Code &&
+                                             i.IsAdmin == invitation.IsAdmin &&
+                                             i.DateCreated == invitation.DateCreated &&
+                                             i.EndDate == invitation.EndDate &&
+                                             i.Description == invitation.Description &&
+                                             i.MaxParticipants == invitation.MaxParticipants
+            
+        );
     }
 
     public bool Exist(Guid guid)
     {
-        throw new NotImplementedException();
+        return _context.Invitations.Any(i => i.Id == guid);
     }
 }
\ No newline at end of file