diff --git a/flake.nix b/flake.nix
index 665dec999..7a896c1cc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -28,6 +28,7 @@
             ocamlPackages.stdint
             ocamlPackages.batteries
             ocamlPackages.zarith
+            ocamlPackages.mtime
           ];
           installPhase = ''
             mkdir -p $out