diff --git a/README.md b/README.md
index 17292b5..10cc379 100644
--- a/README.md
+++ b/README.md
@@ -16,14 +16,14 @@ You might choose to simply copy the derivations from this repository, or you can
 
 ```
 > nix repl
-nix-repl> pkgs = import <nixpkgs> {}
+nix-repl> pkgs = import ./nixpkgs.nix {}
 
 nix-repl> drvs = import (pkgs.fetchFromGitHub {
   owner = "justinwoo";
   repo = "easy-dhall-nix";
   rev = # some REV
   sha256 = # some SHA
-}) {}
+}) { inherit pkgs; }
 
 nix-repl> drvs.dhall-simple
 «derivation /nix/store/qz29jbplpmlvsbmq05084dh1fbs8sl0h-dhall-simple.drv»
diff --git a/default.nix b/default.nix
index 34cbe4c..85c9cbf 100644
--- a/default.nix
+++ b/default.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 {
   dhall-simple = import ./dhall-simple.nix {
diff --git a/dhall-bash-simple.nix b/dhall-bash-simple.nix
index 2704763..9ff2296 100644
--- a/dhall-bash-simple.nix
+++ b/dhall-bash-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-bash-simple";
diff --git a/dhall-docs-simple.nix b/dhall-docs-simple.nix
index 3b581f4..ac54212 100644
--- a/dhall-docs-simple.nix
+++ b/dhall-docs-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> { } }:
+{ pkgs ? import ./nixpkgs.nix { } }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-docs-simple";
diff --git a/dhall-json-simple.nix b/dhall-json-simple.nix
index cceb52a..cfdf524 100644
--- a/dhall-json-simple.nix
+++ b/dhall-json-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-json-simple";
diff --git a/dhall-lsp-simple.nix b/dhall-lsp-simple.nix
index 9c12846..bf15163 100644
--- a/dhall-lsp-simple.nix
+++ b/dhall-lsp-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-lsp-simple";
diff --git a/dhall-nix-simple.nix b/dhall-nix-simple.nix
index 3c3c5c5..21fa5a0 100644
--- a/dhall-nix-simple.nix
+++ b/dhall-nix-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-nix-simple";
diff --git a/dhall-simple.nix b/dhall-simple.nix
index f37bef5..9d419ea 100644
--- a/dhall-simple.nix
+++ b/dhall-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-simple";
diff --git a/dhall-yaml-simple.nix b/dhall-yaml-simple.nix
index 1c0a8cd..f672652 100644
--- a/dhall-yaml-simple.nix
+++ b/dhall-yaml-simple.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 import ./build.nix { inherit pkgs; release = import ./release.nix; } {
   simpleName = "dhall-yaml-simple";
diff --git a/test.nix b/test.nix
index b408f6f..2c94b25 100644
--- a/test.nix
+++ b/test.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nixpkgs.nix {} }:
 
 let