diff --git a/default.nix b/default.nix
index c0d3d7f5a4ec51f39fa0d64486e3051f5788d6dc..f1c5e37ea433eb5add61f81b6c9ed3c4b359ce25 100644
--- a/default.nix
+++ b/default.nix
@@ -1,2 +1,2 @@
-{ pkgs ? import <nixpkgs> { overlays = [ (import ./overlays.nix) ]; } }:
+{ pkgs ? import ./nixpkgs.nix { } }:
 pkgs.python27Packages.callPackage ./zkapauthorizer.nix { }
diff --git a/shell.nix b/shell.nix
index 9831badbecba81acb54a50f95fe677e6ca9a57e6..82afac579e08b5fe57cd8fb8e787fbdd19e78605 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> { overlays = [ (import ./overlays.nix) ]; } }:
+{ pkgs ? import ./nixpkgs.nix { } }:
 let
   zkapauthorizer = pkgs.callPackage ./default.nix { };
 in