diff --git a/src/WebUI/Controllers/ApiControllerBase.cs b/src/WebUI/Controllers/ApiControllerBase.cs
index 160967ba2..80c9f8ee5 100644
--- a/src/WebUI/Controllers/ApiControllerBase.cs
+++ b/src/WebUI/Controllers/ApiControllerBase.cs
@@ -8,7 +8,7 @@ namespace CleanArchitecture.WebUI.Controllers;
 [Route("api/[controller]")]
 public abstract class ApiControllerBase : ControllerBase
 {
-    private ISender _mediator = null!;
+    private ISender? _mediator;
 
     protected ISender Mediator => _mediator ??= HttpContext.RequestServices.GetRequiredService<ISender>();
 }