diff --git a/nixpacks.toml b/nixpacks.toml
index fea2eea..fb542e5 100644
--- a/nixpacks.toml
+++ b/nixpacks.toml
@@ -1,5 +1,6 @@
 [phases.install]
 aptPkgs = ["...", "build-essential"]
+cmds = ["...", "npm install --global yarn"]
 
 [phases.build]
 cmds = ["mix compile", "mix ecto.setup", "pushd assets && yarn install && popd"]