diff --git a/guix-data-service/web/controller.scm b/guix-data-service/web/controller.scm
index 608a4e0..5fe9c1d 100644
--- a/guix-data-service/web/controller.scm
+++ b/guix-data-service/web/controller.scm
@@ -652,7 +652,9 @@
        (match (with-resource-from-pool (connection-pool) conn
                 (select-derivation-source-file-by-store-path conn filename))
          (()
-          (render-json '((error . "store item not found"))))
+          (render-json
+           '((error . "store item not found"))
+           #:code 404))
          ((id)
           (render-json
            `((derivation-source-file