diff --git a/opensearch/client.go b/opensearch/client.go
index c2ba28b..0292dec 100644
--- a/opensearch/client.go
+++ b/opensearch/client.go
@@ -328,13 +328,13 @@ func NewClient(ctx context.Context, cfg Config) (Client, error) {
 		indexPrefix = "ds-logs-" + indexPrefix
 	}
 
-	authHeader := fmt.Sprintf("Basic %s", base64.RawURLEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", cfg.Username, cfg.Password))))
-
 	bulkHeader := make(http.Header)
-	bulkHeader.Set("Authorization", authHeader)
-
 	singleHeader := make(http.Header)
-	singleHeader.Set("Authorization", authHeader)
+	if len(cfg.Username) > 0 && len(cfg.Password) > 0 {
+		authHeader := fmt.Sprintf("Basic %s", base64.RawURLEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", cfg.Username, cfg.Password))))
+		bulkHeader.Set("Authorization", authHeader)
+		singleHeader.Set("Authorization", authHeader)
+	}
 
 	out := Client{
 		Client:               client,