diff --git a/docs/en/docs/tutorial/server-sent-events.md b/docs/en/docs/tutorial/server-sent-events.md
index d16f71ec26..a893510c22 100644
--- a/docs/en/docs/tutorial/server-sent-events.md
+++ b/docs/en/docs/tutorial/server-sent-events.md
@@ -107,7 +107,7 @@ This is useful for protocols like HTML specification: Server-Sent Events.
+* Send a **"keep alive" `ping` comment** every 15 seconds when there hasn't been any message, to prevent some proxies from closing the connection, as suggested in the HTML specification: Server-Sent Events.
* Set the `Cache-Control: no-cache` header to **prevent caching** of the stream.
* Set a special header `X-Accel-Buffering: no` to **prevent buffering** in some proxies like Nginx.