diff --git a/smol-http/util.rkt b/smol-http/util.rkt
index a85eedc..e02565d 100644
--- a/smol-http/util.rkt
+++ b/smol-http/util.rkt
@@ -16,6 +16,7 @@
 (define http-status-codes
   #hasheqv([200 . "OK"]
            [301 . "Moved Permanently"]
+           [400 . "Invalid Request"]
            [403 . "Forbidden"]
            [404 . "Not Found"]
            [500 . "Internal Server Error"]))