diff --git a/SimpleHttpServer/HttpServer.cs b/SimpleHttpServer/HttpServer.cs
index 1473e8a..2df5293 100644
--- a/SimpleHttpServer/HttpServer.cs
+++ b/SimpleHttpServer/HttpServer.cs
@@ -328,10 +328,18 @@ public sealed class HttpServer {
                     var splittedReqPath = reqPath[1..].Split('/');
                     for (int i = 0; i < pparams.Count; i++) {
                         var pparam = pparams[i];
+                        string paramValue;
                         if (pparam.IsCatchAll)
-                            convertedMParamValues[pparam.ArgPos] = string.Join('/', splittedReqPath[pparam.SegmentStartPos..]);
+                            paramValue = string.Join('/', splittedReqPath[pparam.SegmentStartPos..]);
                         else
-                            convertedMParamValues[pparam.ArgPos] = splittedReqPath[pparam.SegmentStartPos];
+                            paramValue = splittedReqPath[pparam.SegmentStartPos];
+
+                        if (stringToTypeParameterConverters[pparam.Type].TryConvertFromString(paramValue, out var res))
+                            convertedMParamValues[pparam.ArgPos] = res;
+                        else {
+                            await HandleDefaultErrorPageAsync(rc, HttpStatusCode.BadRequest);
+                            return;
+                        }
                     }
                 }