diff --git a/libbeat/template/load_integration_test.go b/libbeat/template/load_integration_test.go
index 63db5965f3bb..e1d6c12311a3 100644
--- a/libbeat/template/load_integration_test.go
+++ b/libbeat/template/load_integration_test.go
@@ -370,7 +370,7 @@ func TestESLoader_Load(t *testing.T) {
 					require.NoError(t, err)
 					p, ok := val.(map[string]interface{})
 					require.True(t, ok)
-					var properties []string
+					properties := make([]string, 0, len(p))
 					for k := range p {
 						properties = append(properties, k)
 					}
diff --git a/x-pack/filebeat/input/httpjson/transform_registry.go b/x-pack/filebeat/input/httpjson/transform_registry.go
index 53caa9ded4f4..26a739494db1 100644
--- a/x-pack/filebeat/input/httpjson/transform_registry.go
+++ b/x-pack/filebeat/input/httpjson/transform_registry.go
@@ -52,7 +52,7 @@ func (reg registry) String() string {
 
 	var str string
 	for namespace, m := range reg.namespaces {
-		var names []string
+		names := make([]string, 0, len(m))
 		for k := range m {
 			names = append(names, k)
 		}