diff --git a/src/Backend/DiunaBI.WebAPI/DiunaBI.WebAPI.csproj b/src/Backend/DiunaBI.WebAPI/DiunaBI.WebAPI.csproj
index 1e36bac..70ccdda 100644
--- a/src/Backend/DiunaBI.WebAPI/DiunaBI.WebAPI.csproj
+++ b/src/Backend/DiunaBI.WebAPI/DiunaBI.WebAPI.csproj
@@ -13,6 +13,10 @@
     <PackageReference Include="Google.Apis.Drive.v3" Version="1.68.0.3627" />
     <PackageReference Include="Google.Apis.Sheets.v4" Version="1.68.0.3624" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.0" />
+    <PackageReference Include="Serilog.AspNetCore" Version="9.0.0" />
+    <PackageReference Include="Serilog.Enrichers.Environment" Version="3.0.1" />
+    <PackageReference Include="Serilog.Sinks.File" Version="7.0.0" />
+    <PackageReference Include="Serilog.Sinks.Seq" Version="9.0.0" />
     <PackageReference Include="System.Configuration.ConfigurationManager" Version="8.0.0" />
   </ItemGroup>
 
@@ -34,8 +38,7 @@
   </ItemGroup>
 
   <Target Name="CopyPlugins" AfterTargets="Build">
-    <MSBuild Projects="../DiunaBI.Plugins.Morska/DiunaBI.Plugins.Morska.csproj" 
-            Properties="Configuration=$(Configuration);TargetFramework=$(TargetFramework)" />
+    <MSBuild Projects="../DiunaBI.Plugins.Morska/DiunaBI.Plugins.Morska.csproj" Properties="Configuration=$(Configuration);TargetFramework=$(TargetFramework)" />
     
     <ItemGroup>
       <PluginFiles Include="../DiunaBI.Plugins.Morska/bin/$(Configuration)/$(TargetFramework)/DiunaBI.Plugins.Morska.dll" />
diff --git a/src/Backend/DiunaBI.WebAPI/Program.cs b/src/Backend/DiunaBI.WebAPI/Program.cs
index c8d920c..98017b8 100644
--- a/src/Backend/DiunaBI.WebAPI/Program.cs
+++ b/src/Backend/DiunaBI.WebAPI/Program.cs
@@ -10,9 +10,22 @@ using System.Text;
 using DiunaBI.Database.Context;
 using DiunaBI.Core.Services;
 using Google.Apis.Sheets.v4;
+using Serilog;
 
 var builder = WebApplication.CreateBuilder(args);
 
+// ✅ DODAJ SERILOG CONFIGURATION
+builder.Host.UseSerilog((context, configuration) =>
+{
+    configuration
+        .ReadFrom.Configuration(context.Configuration)
+        .Enrich.FromLogContext()
+        .Enrich.WithProperty("Application", "DiunaBI")
+        .Enrich.WithProperty("Version", Assembly.GetExecutingAssembly().GetName().Version?.ToString() ?? "unknown")
+        .Enrich.WithEnvironmentName()
+        .Enrich.WithMachineName();
+});
+
 var connectionString = builder.Configuration.GetConnectionString("SQLDatabase");
 builder.Services.AddDbContext<AppDbContext>(x =>
 {
@@ -91,12 +104,37 @@ builder.Services.AddSingleton<PluginManager>();
 
 var app = builder.Build();
 
-var pluginManager = app.Services.GetRequiredService<PluginManager>();
+// ✅ DODAJ SERILOG REQUEST LOGGING
+app.UseSerilogRequestLogging(options =>
+{
+    options.MessageTemplate = "HTTP {RequestMethod} {RequestPath} responded {StatusCode} in {Elapsed:0.0000} ms";
+    options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
+    {
+        diagnosticContext.Set("RequestHost", httpContext.Request.Host.Value);
+        diagnosticContext.Set("RequestScheme", httpContext.Request.Scheme);
+        
+        // ✅ POPRAW NULLABLE WARNING
+        var userAgent = httpContext.Request.Headers.UserAgent.FirstOrDefault();
+        if (!string.IsNullOrEmpty(userAgent))
+        {
+            diagnosticContext.Set("UserAgent", userAgent);
+        }
+        
+        // Dodaj więcej użytecznych właściwości
+        diagnosticContext.Set("RemoteIP", httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown");
+        diagnosticContext.Set("RequestContentType", httpContext.Request.ContentType ?? "none");
+    };
+});
 
+// Załaduj pluginy - z logowaniem
+var pluginManager = app.Services.GetRequiredService<PluginManager>();
 var executablePath = Assembly.GetExecutingAssembly().Location;
 var executableDir = Path.GetDirectoryName(executablePath)!;
 var pluginsPath = Path.Combine(executableDir, "Plugins");
 
+Log.Information("Starting DiunaBI application");
+Log.Information("Loading plugins from: {PluginsPath}", pluginsPath);
+
 pluginManager.LoadPluginsFromDirectory(pluginsPath);
 
 app.Use(async (context, next) =>
@@ -122,3 +160,6 @@ app.UseAuthorization();
 app.MapControllers();
 
 app.Run();
+
+// ✅ DODAJ CLEANUP
+Log.CloseAndFlush();
diff --git a/src/Backend/DiunaBI.WebAPI/appsettings.json b/src/Backend/DiunaBI.WebAPI/appsettings.json
index 01e744b..89147f0 100644
--- a/src/Backend/DiunaBI.WebAPI/appsettings.json
+++ b/src/Backend/DiunaBI.WebAPI/appsettings.json
@@ -7,6 +7,44 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
+  "Serilog": {
+    "MinimumLevel": {
+      "Default": "Information",
+      "Override": {
+        "Microsoft.AspNetCore": "Warning",
+        "Microsoft.EntityFrameworkCore.Database.Command": "Warning",
+        "Microsoft.EntityFrameworkCore.Infrastructure": "Warning",
+        "System.Net.Http.HttpClient": "Warning",
+        "Google.Apis": "Warning",
+        "DiunaBI.Core.Services.PluginManager": "Information"
+      }
+    },
+    "WriteTo": [
+      {
+        "Name": "Console",
+        "Args": {
+          "outputTemplate": "[{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}"
+        }
+      },
+      {
+        "Name": "File",
+        "Args": {
+          "path": "/var/log/diunabi/app-.log",
+          "rollingInterval": "Day",
+          "retainedFileCountLimit": 30,
+          "outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level:u3}] {SourceContext} {Message:lj} {Properties:j}{NewLine}{Exception}"
+        }
+      },
+      {
+        "Name": "Seq",
+        "Args": {
+          "serverUrl": "http://localhost:5341",
+          "restrictedToMinimumLevel": "Information"
+        }
+      }
+    ],
+    "Enrich": ["FromLogContext", "WithMachineName", "WithThreadId"]
+  },
   "AllowedHosts": "*",
   "ConnectionStrings": {
     "SQLDatabase": "#{db-connection-string}#"