diff --git a/flake.nix b/flake.nix
index 62151afb6..e607cca53 100644
--- a/flake.nix
+++ b/flake.nix
@@ -49,6 +49,7 @@
     nixpkgsArgs.config.permittedInsecurePackages = [
       "nodejs-14.21.3"
       "openssl-1.1.1w"
+      "python-2.7.18.7"
     ];
   };
 
diff --git a/nix/marlowe-playground-client.nix b/nix/marlowe-playground-client.nix
index bcab67292..cccfcaec4 100644
--- a/nix/marlowe-playground-client.nix
+++ b/nix/marlowe-playground-client.nix
@@ -1,73 +1,55 @@
-{ repoRoot, inputs, pkgs, system, lib }:
+{ repoRoot, inputs, pkgs, ... }:
 
 let
-  spago-pkgs = import ./spago-packages.nix { inherit pkgs; };
-in
-
-pkgs.buildNpmPackage {
-
-  pname = "marlowe-playground-client";
-
-  version = "0.1.0";
-
-  src = lib.sourceByRegex (inputs.self + /marlowe-playground-client) [
-    "^prototype.*"
-    "^generated.*"
-    "^src.*"
-    "^static.*"
-    "^test.*"
-    "^entry.*"
-    "^grammar.ne$"
-    "^package.*"
-    "^postcss.*"
-    "^spago.*"
-    "^tailwind.*"
-    "^tsconfig.*"
-    "^webpack.*"
-  ];
-
-  dontNpmBuild = true;
-  dontNpmInstall = true;
+  npmlock2nix = import inputs.npmlock2nix { inherit pkgs; };
 
-  # buildNpmPackage is able to make a pure nix build by using npmDepsHash.
-  # That is the hash of package-lock.json.
-  # Its value is generated using the prefetch-npm-deps command (see shell.nix).
-  # We set dontNpmBuild and dontNpmInstall to true to significantly speed up the 
-  # build: this works because we have a custom buildPhase that invokes webpack-cli
-  # explicitely.
-  npmDepsHash = import ./npm-deps-hash.nix;
+  spagoPkgs = import ./spago-packages.nix { inherit pkgs; };
+in
 
-  nativeBuildInputs = [
-    spago-pkgs.installSpagoStyle
-    spago-pkgs.buildSpagoStyle
+npmlock2nix.v1.build {
+  src = inputs.self + "/marlowe-playground-client";
+  installPhase = ''
+    mkdir -p $out/share/marlowe-playground-client/
+    cp -r dist $out/share/marlowe-playground-client/static
+  '';
+  node_modules_attrs = {
+    githubSourceHashMap = {
+      shmish111.nearley-webpack-loader."939360f9d1bafa9019b6ff8739495c6c9101c4a1" = "1brx669dgsryakf7my00m25xdv7a02snbwzhzgc9ylmys4p8c10x";
+      ankitrohatgi.tarballjs."64ea5eb78f7fc018a223207e67f4f863fcc5d3c5" = "04r9yap0ka4y3yirg0g7xb63mq7jzc2qbgswbixxj8s60k6zdqsm";
+    };
+    buildInputs = [ pkgs.python ];
+  };
+  buildInputs = [
+    spagoPkgs.installSpagoStyle
+    spagoPkgs.buildSpagoStyle
+    pkgs.nodejs-14_x
     repoRoot.nix.easy-purescript-nix.purs
     repoRoot.nix.easy-purescript-nix.spago2nix
-    pkgs.nodejs_14
-    pkgs.nodejs_14.pkgs.webpack
-    pkgs.nodejs_14.pkgs.webpack-cli
   ];
-
-  buildPhase = ''
-    mkdir -p {marlowe-playground-client,web-common-marlowe,web-common}
-
+  unpackPhase = ''
+    mkdir -p marlowe-playground-client
     cp -r $src/* marlowe-playground-client
+
+    mkdir -p web-common-marlowe
     cp -r ${inputs.self + "/web-common-marlowe"}/* web-common-marlowe
+
+    mkdir -p web-common
     cp -r ${inputs.self + "/web-common"}/* web-common
 
-    cd marlowe-playground-client 
-    
+    cd marlowe-playground-client
     install-spago-style
-
-    build-spago-style \
-      "./src/**/*.purs" \
-      "./generated/**/*.purs" \
-      "../web-common-marlowe/src/**/*.purs" \
-      "../web-common/src/**/*.purs"
-
-    npm run build:webpack:prod
-
-    mkdir -p $out/share/marlowe-playground-client/static
-
-    cp -r dist $out/share/marlowe-playground-client/static
+    cd ..
   '';
+  buildCommands = [
+    ''
+      cd marlowe-playground-client
+      build-spago-style \
+        "./src/**/*.purs" \
+        "./generated/**/*.purs" \
+        "../web-common-marlowe/src/**/*.purs" \
+        "../web-common/src/**/*.purs"
+      rm -rf ./dist
+      npm run build:webpack:prod
+    ''
+  ];
 }