diff --git a/Pilz.Net/Api/ApiServer.cs b/Pilz.Net/Api/ApiServer.cs
index d194207..522080b 100644
--- a/Pilz.Net/Api/ApiServer.cs
+++ b/Pilz.Net/Api/ApiServer.cs
@@ -94,9 +94,9 @@ public class ApiServer(string apiUrl) : IApiServer
             {
                 var name = url.Substring(nextBreacket + 1, endBreacket - nextBreacket - 1);
                 const string regex = "[A-Za-z0-9%]+";
-                url = url.Replace(url.Substring(nextBreacket, endBreacket + 1), regex);
+                url = url.Replace(url.Substring(nextBreacket, endBreacket - nextBreacket + 1), regex);
 
-                var index = url.Substring(0, nextBreacket + 1).Split('/').Length;
+                var index = url[..(nextBreacket + 1)].Split('/').Length - 1;
                 parameters.Add(new(name, index));
 
                 useRegEx = true;