diff --git a/content/client-server-api/_index.md b/content/client-server-api/_index.md
index b0ce7289..837d3068 100644
--- a/content/client-server-api/_index.md
+++ b/content/client-server-api/_index.md
@@ -227,7 +227,7 @@ return a standard error response of the form:
 ```
 
 Homeservers SHOULD include a [`Retry-After`](https://www.rfc-editor.org/rfc/rfc9110#field.retry-after)
-for any response with a 429 status code.
+header for any response with a 429 status code.
 
 The `retry_after_ms` property MAY be included to tell the client how long
 they have to wait in milliseconds before they can try again. This property is