diff --git a/.nix/flake.nix b/.nix/flake.nix
index 8ea9b96..ee64884 100644
--- a/.nix/flake.nix
+++ b/.nix/flake.nix
@@ -15,6 +15,7 @@
             # building
             gcc
             cmake
+            ninja
             sccache
 
             # pre-commit