diff --git a/src/ActiveDirectoryToRestApi/Authentication/ApiKeyAuthFilter.cs b/src/ActiveDirectoryToRestApi/Authentication/ApiKeyAuthFilter.cs
new file mode 100644
index 0000000..5fafb6d
--- /dev/null
+++ b/src/ActiveDirectoryToRestApi/Authentication/ApiKeyAuthFilter.cs
@@ -0,0 +1,31 @@
+namespace ActiveDirectoryToRestApi.Authentication;
+
+public class ApiKeyAuthFilter : IAuthorizationFilter
+{
+    private readonly Configuration _configuration;
+
+    public ApiKeyAuthFilter(IConfiguration configuration)
+    {
+        _configuration = configuration.GetSection(nameof(Configuration)).Get<Configuration>();
+    }
+
+    public void OnAuthorization(AuthorizationFilterContext context)
+    {
+        if (_configuration.AuthEnabled)
+        {
+            if (!context.HttpContext.Request.Headers.TryGetValue("Authorization", out var extractedAuthToken))
+            {
+                context.Result = new UnauthorizedObjectResult("Authorization token was not provided");
+                return;
+            }
+
+            var authToken = _configuration.Authorization;
+
+            if (!authToken.Equals(extractedAuthToken))
+            {
+                context.Result = new UnauthorizedObjectResult("Unauthorized client");
+                return;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/ActiveDirectoryToRestApi/Configurations/Configuration.cs b/src/ActiveDirectoryToRestApi/Configurations/Configuration.cs
new file mode 100644
index 0000000..dc098b9
--- /dev/null
+++ b/src/ActiveDirectoryToRestApi/Configurations/Configuration.cs
@@ -0,0 +1,7 @@
+namespace ActiveDirectoryToRestApi.Configurations;
+
+public class Configuration
+{
+    public string Authorization { get; set; }
+    public bool AuthEnabled { get; set; }
+}
diff --git a/src/ActiveDirectoryToRestApi/Controllers/GroupController.cs b/src/ActiveDirectoryToRestApi/Controllers/GroupController.cs
index 10a0b70..e59d2cc 100644
--- a/src/ActiveDirectoryToRestApi/Controllers/GroupController.cs
+++ b/src/ActiveDirectoryToRestApi/Controllers/GroupController.cs
@@ -2,6 +2,7 @@ namespace ActiveDirectoryToRestApi.Controllers;
 
 [ApiController]
 [Route("[controller]")]
+[ServiceFilter(typeof(ApiKeyAuthFilter))]
 public class GroupController : ControllerBase
 {
     private readonly ILogger<GroupController> _logger;
diff --git a/src/ActiveDirectoryToRestApi/Controllers/UserController.cs b/src/ActiveDirectoryToRestApi/Controllers/UserController.cs
index e450c5c..b9bcf29 100644
--- a/src/ActiveDirectoryToRestApi/Controllers/UserController.cs
+++ b/src/ActiveDirectoryToRestApi/Controllers/UserController.cs
@@ -2,6 +2,7 @@ namespace ActiveDirectoryToRestApi.Controllers;
 
 [ApiController]
 [Route("[controller]")]
+[ServiceFilter(typeof(ApiKeyAuthFilter))]
 public class UserController : ControllerBase
 {
     private readonly ILogger<UserController> _logger;
diff --git a/src/ActiveDirectoryToRestApi/GlobalUsings.cs b/src/ActiveDirectoryToRestApi/GlobalUsings.cs
index 368e045..1b3ae75 100644
--- a/src/ActiveDirectoryToRestApi/GlobalUsings.cs
+++ b/src/ActiveDirectoryToRestApi/GlobalUsings.cs
@@ -1,8 +1,11 @@
-global using ActiveDirectoryToRestApi.Configurations;
+global using ActiveDirectoryToRestApi.Authentication;
+global using ActiveDirectoryToRestApi.Configurations;
 global using ActiveDirectoryToRestApi.Extensions;
 global using ActiveDirectoryToRestApi.Models;
 global using ActiveDirectoryToRestApi.Services;
 global using Microsoft.AspNetCore.Mvc;
+global using Microsoft.AspNetCore.Mvc.Filters;
+global using Microsoft.OpenApi.Models;
 global using System.ComponentModel;
 global using System.ComponentModel.DataAnnotations;
 global using System.DirectoryServices.Protocols;
diff --git a/src/ActiveDirectoryToRestApi/Program.cs b/src/ActiveDirectoryToRestApi/Program.cs
index 5b2000a..26fb5ee 100644
--- a/src/ActiveDirectoryToRestApi/Program.cs
+++ b/src/ActiveDirectoryToRestApi/Program.cs
@@ -2,7 +2,31 @@ var builder = WebApplication.CreateBuilder(args);
 
 builder.Services.AddControllers();
 builder.Services.AddEndpointsApiExplorer();
-builder.Services.AddSwaggerGen();
+builder.Services.AddSwaggerGen(s =>
+{
+    s.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
+    {
+        Description = "Enter the token with the `Bearer` prefix, e.g. \"Bearer a1b2c3d4\"",
+        Type = SecuritySchemeType.ApiKey,
+        Name = "Authorization",
+        In = ParameterLocation.Header,
+        Scheme = "ApiKeyScheme",
+    });
+    var scheme = new OpenApiSecurityScheme
+    {
+        Reference = new OpenApiReference
+        {
+            Type = ReferenceType.SecurityScheme,
+            Id = "Bearer"
+        },
+        In = ParameterLocation.Header
+    };
+    var requirement = new OpenApiSecurityRequirement
+    {
+        { scheme, new List<string>() }
+    };
+    s.AddSecurityRequirement(requirement);
+});
 builder.Services.AddSingleton(provider =>
 {
     var configs = builder.Configuration.GetSection(nameof(LdapConfigs)).Get<LdapConfigs>();
@@ -18,6 +42,7 @@ builder.Services.AddSingleton(provider =>
 });
 builder.Services.AddSingleton<LdapService>();
 builder.Services.AddTransient<AuthUserService>();
+builder.Services.AddScoped<ApiKeyAuthFilter>();
 
 var app = builder.Build();
 
diff --git a/src/ActiveDirectoryToRestApi/appsettings.json b/src/ActiveDirectoryToRestApi/appsettings.json
index 49ba635..e5cb290 100644
--- a/src/ActiveDirectoryToRestApi/appsettings.json
+++ b/src/ActiveDirectoryToRestApi/appsettings.json
@@ -12,5 +12,9 @@
     "User": "ldapAdmin",
     "Pass": "Thi$1sMyPassw0rd",
     "DistinguishedName": "DC=ad,DC=zimbres,DC=com"
+  },
+  "Configuration": {
+    "Authorization": "Bearer v63M9FlOhqAohJ7oGmFrhVIj",
+    "AuthEnabled": "false"
   }
 }