diff --git a/templates/astro/flake.nix.twig b/templates/astro/flake.nix.twig
index ba5eff8..8180f23 100644
--- a/templates/astro/flake.nix.twig
+++ b/templates/astro/flake.nix.twig
@@ -3,7 +3,7 @@
 {
   inputs = {
     devshell.url = "github:numtide/devshell";
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
   };
 
   outputs = inputs@{ flake-parts, ... }:
diff --git a/templates/fractal/flake.nix.twig b/templates/fractal/flake.nix.twig
index ba5eff8..8180f23 100644
--- a/templates/fractal/flake.nix.twig
+++ b/templates/fractal/flake.nix.twig
@@ -3,7 +3,7 @@
 {
   inputs = {
     devshell.url = "github:numtide/devshell";
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
   };
 
   outputs = inputs@{ flake-parts, ... }: