diff --git a/compat/fetch.nix b/compat/fetch.nix
new file mode 100644
index 00000000..01f0f02f
--- /dev/null
+++ b/compat/fetch.nix
@@ -0,0 +1,17 @@
+let
+  inherit (builtins)
+    fetchTarball
+    fromJSON
+    readFile
+    ;
+  lockfile = fromJSON (readFile ../flake.lock);
+in
+input:
+let
+  locked = lockfile.nodes."${input}".locked;
+  inherit (locked) rev narHash owner repo;
+in
+fetchTarball {
+  url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz";
+  sha256 = narHash;
+}
diff --git a/compat/nixpkgs.nix b/compat/nixpkgs.nix
new file mode 100644
index 00000000..3dd503a9
--- /dev/null
+++ b/compat/nixpkgs.nix
@@ -0,0 +1,5 @@
+let
+  fetch = import ./fetch.nix;
+  nixpkgs = fetch "nixos";
+in
+nixpkgs
diff --git a/nixpkgs-compat.nix b/nixpkgs-compat.nix
deleted file mode 100644
index 08b07372..00000000
--- a/nixpkgs-compat.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-let
-  inherit (builtins)
-    fetchTarball
-    fromJSON
-    readFile
-    ;
-  nixos = (fromJSON (readFile ./flake.lock)).nodes.nixos.locked;
-  nixpkgs = fetchTarball {
-    url = "https://github.com/NixOS/nixpkgs/archive/${nixos.rev}.tar.gz";
-    sha256 = nixos.narHash;
-  };
-in
-nixpkgs
diff --git a/shell.nix b/shell.nix
index 5aae2efc..dadb9e7f 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,5 +1,5 @@
 let
-  nixpkgs' = import ./nixpkgs-compat.nix;
+  nixpkgs = import ./compat/nixpkgs.nix;
 in
 { pkgs ? import nixpkgs { }, nixpkgs ? nixpkgs' }:
 let