diff --git a/error.go b/error.go
index 09290c0..88e9d4a 100644
--- a/error.go
+++ b/error.go
@@ -41,7 +41,7 @@ func httpErr(prefix string, err error, r *http.Response, body []byte) *Error {
 		inner:   err,
 		Msg:     prefix + err.Error(),
 		Status:  r.StatusCode,
-		Headers: uniqueHeaders(r.Header),
+		Headers: mapFlatten(r.Header),
 		Body:    string(body),
 	}
 }
diff --git a/fetch.go b/fetch.go
index aec9763..8360976 100644
--- a/fetch.go
+++ b/fetch.go
@@ -170,7 +170,7 @@ func Do[T any](url string, config ...Config) (T, error) {
 	if isResponseWithEmpty(t) && firstDigit(res.StatusCode) == 2 {
 		re := any(&t).(*Response[Empty])
 		re.Status = res.StatusCode
-		re.Headers = uniqueHeaders(res.Header)
+		re.Headers = mapFlatten(res.Header)
 		return t, nil
 	}
 
@@ -198,7 +198,7 @@ func Do[T any](url string, config ...Config) (T, error) {
 
 		valueOf := reflect.Indirect(reflect.ValueOf(&t))
 		valueOf.FieldByName("Status").SetInt(int64(res.StatusCode))
-		valueOf.FieldByName("Headers").Set(reflect.ValueOf(uniqueHeaders(res.Header)))
+		valueOf.FieldByName("Headers").Set(reflect.ValueOf(mapFlatten(res.Header)))
 		valueOf.FieldByName("Body").Set(reflect.ValueOf(resInstance).Elem())
 
 		return t, nil
diff --git a/to_handler.go b/to_handler.go
index 4d51839..415b290 100644
--- a/to_handler.go
+++ b/to_handler.go
@@ -80,7 +80,8 @@ func ToHandlerFunc[In any, Out any](apply ApplyFunc[In, Out]) http.HandlerFunc {
 			valueOf := reflect.Indirect(reflect.ValueOf(&in))
 			valueOf.FieldByName("PathValues").Set(reflect.ValueOf(extractPathValues(r)))
 			valueOf.FieldByName("Context").Set(reflect.ValueOf(r.Context()))
-			valueOf.FieldByName("Headers").Set(reflect.ValueOf(uniqueHeaders(r.Header)))
+			valueOf.FieldByName("Parameters").Set(reflect.ValueOf(mapFlatten(r.URL.Query())))
+			valueOf.FieldByName("Headers").Set(reflect.ValueOf(mapFlatten(r.Header)))
 			valueOf.FieldByName("Body").Set(reflect.ValueOf(resInstance).Elem())
 		} else if !isEmptyType(in) {
 			err := readAndParseBody(r, &in)
diff --git a/to_handler_test.go b/to_handler_test.go
index 7f5deb9..c32c755 100644
--- a/to_handler_test.go
+++ b/to_handler_test.go
@@ -87,6 +87,22 @@ func TestToHandlerFunc_Header(t *testing.T) {
 	assert(t, mw.status, 200)
 }
 
+func TestToHandlerFunc_UrlParameter(t *testing.T) {
+	f := ToHandlerFunc(func(in Request[Empty]) (Empty, error) {
+		if in.Parameters["name"] != "Lola" {
+			t.Errorf("wrong in %v", in)
+		}
+		return Empty{}, nil
+	})
+	mw := newMockWriter()
+	mux := http.NewServeMux()
+	mux.HandleFunc("/pets", f)
+	r, err := http.NewRequest("POST", "/pets?name=Lola", bytes.NewBuffer([]byte(``)))
+	assert(t, err, nil)
+	mux.ServeHTTP(mw, r)
+	assert(t, mw.status, 200)
+}
+
 func TestToHandlerFunc_ParseErrors(t *testing.T) {
 	t.Run("Empty Request Body, Struct with fields", func(t *testing.T) {
 		type Pet struct {
diff --git a/wrappers.go b/wrappers.go
index be9edff..949284e 100644
--- a/wrappers.go
+++ b/wrappers.go
@@ -29,15 +29,15 @@ type Response[T any] struct {
 	Body    T
 }
 
-func uniqueHeaders(headers map[string][]string) map[string]string {
-	h := make(map[string]string, len(headers))
-	for key, val := range headers {
+func mapFlatten(m map[string][]string) map[string]string {
+	newM := make(map[string]string, len(m))
+	for key, val := range m {
 		if len(val) > 0 {
 			// it takes the last element intentionally.
-			h[key] = val[len(val)-1]
+			newM[key] = val[len(val)-1]
 		}
 	}
-	return h
+	return newM
 }
 
 /*
@@ -60,8 +60,11 @@ type Request[T any] struct {
 	// there was no reliable way to extract them.
 	// go1.23 introduced http.Request.Pattern allowing to list the wildcards.
 	PathValues map[string]string
-	Headers    map[string]string
-	Body       T
+	// URL parameters.
+	Parameters map[string]string
+	// HTTP headers.
+	Headers map[string]string
+	Body    T
 }
 
 // Empty represents an empty response or request body, skipping JSON handling.