diff --git a/FinancialTracker.API.sln.DotSettings.user b/FinancialTracker.API.sln.DotSettings.user
index 642f398..e1c0ea2 100644
--- a/FinancialTracker.API.sln.DotSettings.user
+++ b/FinancialTracker.API.sln.DotSettings.user
@@ -1,4 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AOpenApiInfo_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003FAppData_003FRoaming_003FJetBrains_003FRider2025_002E2_003Fresharper_002Dhost_003FSourcesCache_003Ffcedb617b237dc31e998d31e01f101e8441948433938518c5f20cec1a845c1_003FOpenApiInfo_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=c3e35030_002D771d_002D4674_002D85e8_002D2b16dd384d0f/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" IsActive="True" Name="All tests from Solution" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;&#xD;
   &lt;Solution /&gt;&#xD;
 &lt;/SessionState&gt;</s:String></wpf:ResourceDictionary>
\ No newline at end of file
diff --git a/FinancialTracker/Data/Entities/Transaction.cs b/FinancialTracker/Data/Entities/Transaction.cs
index 69e9b64..69615ea 100644
--- a/FinancialTracker/Data/Entities/Transaction.cs
+++ b/FinancialTracker/Data/Entities/Transaction.cs
@@ -8,9 +8,9 @@ public class Transaction
     public required string Description { get; set; }
     
     [Column(TypeName = "decimal(18,2)")]
-    public decimal Amount { get; set; }
+    public required decimal Amount { get; set; }
     public DateTime Date { get; set; } = DateTime.UtcNow;
     
-    public int CategoryId { get; set; }
+    public required int CategoryId { get; set; }
     public Category Category { get; set; } = null!;
 }
\ No newline at end of file
diff --git a/FinancialTracker/FinancialTracker.csproj b/FinancialTracker/FinancialTracker.csproj
index 3e830d5..ca3bed5 100644
--- a/FinancialTracker/FinancialTracker.csproj
+++ b/FinancialTracker/FinancialTracker.csproj
@@ -11,6 +11,7 @@
         <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.1" />
         <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.1" />
         <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.1" />
+        <PackageReference Include="Swashbuckle.AspNetCore" Version="9.0.4" />
     </ItemGroup>
 
     <ItemGroup>
diff --git a/FinancialTracker/Program.cs b/FinancialTracker/Program.cs
index 49dafdf..d5687b6 100644
--- a/FinancialTracker/Program.cs
+++ b/FinancialTracker/Program.cs
@@ -3,6 +3,7 @@
 using FinancialTracker.Interfaces;
 using FinancialTracker.Services;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.OpenApi.Models;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -15,6 +16,17 @@
 builder.Services.AddDbContext<FinancialDbContext>(options => 
     options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection")));
 
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen(c =>
+{
+    c.SwaggerDoc("v1", new OpenApiInfo
+    {
+        Title = "Financial Tracker API",
+        Version = "v1",
+        Description = "API для управления личными финансами",
+    });
+});
+
 var app = builder.Build();
 
 using (var scope = app.Services.CreateScope())
@@ -23,6 +35,16 @@
     dbContext.Database.Migrate();
 }
 
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI(c =>
+    {
+        c.SwaggerEndpoint("/swagger/v1/swagger.json", "Financial Tracker API v1");
+        c.RoutePrefix = "swagger";
+    });
+}
+
 app.UseRouting();
 app.MapControllers();
 
diff --git a/FinancialTracker/Services/TransactionService.cs b/FinancialTracker/Services/TransactionService.cs
index 7254e7d..0196238 100644
--- a/FinancialTracker/Services/TransactionService.cs
+++ b/FinancialTracker/Services/TransactionService.cs
@@ -22,6 +22,11 @@ public async Task<List<TransactionResponseDto>> GetAllAsync()
 
     public async Task<TransactionResponseDto> AddAsync(TransactionCreateDto createDto)
     {
+        if (createDto.Amount <= 0)
+        {
+            throw new InvalidOperationException("Сумма транзакции должна быть положительной");
+        }
+        
         var category = await categoryRepository.GetByIdAsync(createDto.CategoryId);
         if (category == null)
         {
@@ -42,6 +47,11 @@ public async Task<TransactionResponseDto> AddAsync(TransactionCreateDto createDt
 
     public async Task<TransactionResponseDto?> UpdateAsync(TransactionUpdateDto updateDto)
     {
+        if (updateDto.Amount <= 0)
+        {
+            throw new InvalidOperationException("Сумма транзакции должна быть положительной");
+        }
+        
         var existingTransaction = await transactionRepository.GetByIdAsync(updateDto.Id);
         if (existingTransaction == null)
             return null;