diff --git a/README.md b/README.md
index 2df453e..7a0e241 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,7 @@ More configuration parameters:
 - `port`: listen port (default: 24231)
 - `metrics_path`: metrics HTTP endpoint (default: /metrics)
 - `aggregated_metrics_path`: metrics HTTP endpoint (default: /aggregated_metrics)
+- `content_encoding`: encoding format for the exposed metrics (default: identity)
 
 When using multiple workers, each worker binds to port + `fluent_worker_id`.
 To scrape metrics from all workers at once, you can access http://localhost:24231/aggregated_metrics.