diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index c4a847d..bdcb645 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
+/.direnv/
 /result
diff --git a/README.markdown b/README.markdown
index 751ace6..4060a8f 100644
--- a/README.markdown
+++ b/README.markdown
@@ -7,13 +7,13 @@ This repository contains files for building
 First, you should update the necessary Nix files:
 
 ``` bash
-nix-shell --run 'bash generate.sh'
+nix develop --command bash generate.sh
 ```
 
 Afterwards, the distribution for financier can be built:
 
 ``` bash
-nix-build dist.nix
+nix build
 ```
 
 There is also a module (module.nix) that you can use in your NixOS
diff --git a/dist.nix b/dist.nix
index efbae55..460be41 100644
--- a/dist.nix
+++ b/dist.nix
@@ -1,12 +1,11 @@
 { pkgs ? import <nixpkgs> { inherit system; }, system ? builtins.currentSystem
-}:
+, financierVersion }:
 
 let
   financier = (import ./default.nix { inherit pkgs system; }).package;
-  meta = import ./meta.nix;
 
 in pkgs.stdenv.mkDerivation {
-  inherit (meta) version;
+  version = financierVersion;
   pname = "financier-dist";
   src = "${financier}/lib/node_modules/financier";
   buildInputs = [ financier.nodejs ];
diff --git a/flake.lock b/flake.lock
index 06833b4..aeca13c 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "financier": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1643285999,
+        "narHash": "sha256-t0fdmgXtL5oh1sORK/9Uv8lDFXW2GCkQg+LGWyo8mXw=",
+        "owner": "mpuppe",
+        "repo": "financier",
+        "rev": "feb17f4bfba2121043be68d6ab74573c6be2a06d",
+        "type": "gitlab"
+      },
+      "original": {
+        "owner": "mpuppe",
+        "repo": "financier",
+        "type": "gitlab"
+      }
+    },
     "flake-utils": {
       "locked": {
         "lastModified": 1631561581,
@@ -31,6 +47,7 @@
     },
     "root": {
       "inputs": {
+        "financier": "financier",
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
diff --git a/flake.nix b/flake.nix
index 6d47e5b..cb89d68 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,8 +1,22 @@
 {
   inputs.flake-utils.url = "github:numtide/flake-utils";
-  outputs = { self, nixpkgs, flake-utils }:
-    let overlay = import ./overlay.nix;
-    in flake-utils.lib.eachDefaultSystem (system:
+  inputs.financier = {
+    url = "gitlab:mpuppe/financier";
+    flake = false;
+  };
+
+  outputs = inputs@{ self, nixpkgs, ... }:
+    let
+      financierVersion = "1.7.3";
+      nodeVersion = "12";
+
+      overlay = final: prev: {
+        financier-dist = import ./dist.nix {
+          inherit financierVersion;
+          inherit (prev) pkgs system;
+        };
+      };
+    in inputs.flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs {
           inherit system;
@@ -11,8 +25,18 @@
       in {
         packages = { inherit (pkgs) financier-dist; };
         defaultPackage = self.packages.${system}.financier-dist;
+        devShell = pkgs.mkShell {
+          packages = with pkgs; [ nodePackages.node2nix ];
+          shellHook = ''
+            export FINANCIER_SRC="${inputs.financier}"
+            export FINANCIER_NODE_VERSION="${nodeVersion}"
+          '';
+        };
       }) // {
         inherit overlay;
-        nixosModule = import ./module.nix;
+        nixosModule = {
+          imports = [ ./module.nix ];
+          nixpkgs.overlays = [ self.overlay ];
+        };
       };
 }
diff --git a/helpers.nix b/helpers.nix
index c109e48..dbeb77b 100644
--- a/helpers.nix
+++ b/helpers.nix
@@ -1,4 +1,12 @@
 {
-  fetchFinancier = { fetchgit, meta ? import ./meta.nix }:
-    fetchgit { inherit (meta) url rev sha256; };
+  fetchFinancier = { fetchgit }:
+    let
+      financierLockData = (builtins.fromJSON
+        (builtins.readFile ./flake.lock)).nodes.financier.locked;
+      inherit (financierLockData) narHash owner repo rev;
+      url = "https://gitlab.com/${owner}/${repo}.git";
+    in fetchgit {
+      inherit url rev;
+      sha256 = narHash;
+    };
 }
diff --git a/meta.nix b/meta.nix
deleted file mode 100644
index 142267b..0000000
--- a/meta.nix
+++ /dev/null
@@ -1,9 +0,0 @@
-rec {
-  version = "1.7.3";
-  nodeVersion = "12";
-
-  # Arguments for fetchgit
-  url = "https://gitlab.com/mpuppe/financier.git";
-  rev = "83367cae265af4a036a05766c6f80ea22d1cc1ec";
-  sha256 = "0h7222j9fk4b3fkc7c6gbhl0xranpl5swapkwibb0aba0g6fykfg";
-}
diff --git a/module.nix b/module.nix
index 35b9086..cea1162 100644
--- a/module.nix
+++ b/module.nix
@@ -29,8 +29,6 @@ in {
   };
 
   config = mkIf cfg.enable {
-    nixpkgs.overlays = [ (import ./overlay.nix) ];
-
     networking.firewall.allowedTCPPorts = [ 80 443 ];
 
     services.nginx = mkIf (cfg.server == "nginx") {
diff --git a/overlay.nix b/overlay.nix
deleted file mode 100644
index 3a03727..0000000
--- a/overlay.nix
+++ /dev/null
@@ -1,3 +0,0 @@
-final: prev: {
-  financier-dist = import ./dist.nix { inherit (prev) pkgs system; };
-}